Method and device for receiving ppdu through multiple rus in wireless lan system

ABSTRACT

Proposed are a method and a device for receiving a PPDU in a wireless LAN system. Specifically, a receiving STA receives a PPDU from a transmitting STA through a first band, and decodes the PPDU. The PPDU comprises a control field and a data field. When the first band is an 80 MHz band comprising first to fourth 20 MHz subchannels, the first 20 MHz subchannel comprises first multiple RUs in which a first 26RU and a first 52RU are aggregated. The first 26RU is an RU located in the middle of the first 20 MHz subchannel. The first 52RU is an RU having a frequency lower than that of the first 26RU, and which is adjacent to the first 26RU.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/781,210, filed on May 31, 2022, which is the National Stage filingunder 35 U.S.C. 371 of International Application No. PCT/KR2020/016453,filed on Nov. 20, 2020, which claims the benefit of earlier filing dateand right of priority to Korean Application No. 10-2019-0156883, filedon Nov. 29, 2019, the contents of which are all incorporated byreference herein in their entirety.

BACKGROUND Technical Field

The present disclosure relates to a technique for receiving a PPDUthrough multiple RUs in a WLAN system, and more particularly, to amethod and apparatus for transmitting and receiving a PPDU throughmultiple RUs aggregated for each 20 MHz in units of an 80 MHzsubchannel.

Related Art

A wireless local area network (WLAN) has been enhanced in various ways.For example, the IEEE 802.1 lax standard has proposed an enhancedcommunication environment by using orthogonal frequency divisionmultiple access (OFDMA) and downlink multi-user multiple input multipleoutput (DL MU MIMO) schemes.

The present specification proposes a technical feature that can beutilized in a new communication standard. For example, the newcommunication standard may be an extreme high throughput (EHT) standardwhich is currently being discussed. The EHT standard may use anincreased bandwidth, an enhanced PHY layer protocol data unit (PPDU)structure, an enhanced sequence, a hybrid automatic repeat request(HARQ) scheme, or the like, which is newly proposed. The EHT standardmay be referred to as the IEEE 802.11be standard.

An increased number of spatial streams may be used in the new wirelessLAN standard. In this case, in order to properly use the increasednumber of spatial streams, a signaling technique in the WLAN system mayneed to be improved.

SUMMARY Technical Objectives

The present disclosure proposes a method and apparatus for receiving aPPDU through multiple RUs in a WLAN system.

Technical Solutions

An example of the present specification proposes a method for receivinga PPDU through the multiple RUs.

This embodiment may be performed in a network environment in which anext-generation wireless LAN system (e.g., IEEE 802.11be or EHT wirelessLAN system) is supported. The next-generation wireless LAN system is awireless LAN system improved from the 802.11 ax system, and may satisfybackward compatibility with the 802.11ax system.

This embodiment proposes a method and apparatus for transmitting andreceiving PPDU based on multiple RUs configured by a combination betweensmall-RUs. In this case, small-RU means a resource unit having less than242 tones. In particular, this embodiment proposes multiple RUs in which26RU and 52RU are aggregated in each 20 MHz subchannel of a band fortransmitting the PPDU.

A receiving station (STA) receives a Physical Protocol Data Unit (PPDU)through a first band from a transmitting STA.

The receiving STA decode the PPDU.

The PPDU includes a control field and a data field.

When the first band is an 80 MHz band including first to fourth 20 MHzsubchannels, the first 20 MHz subchannel includes first multipleresource units (RUs) in which a first 26RU and a first 52RU areaggregated. The first 26RU is an RU located in the middle of the first20 MHz subchannel. The first 52RU is an RU having a lower frequency thanthe first 26RU and is adjacent to the first 26RU.

Technical Effects

According to the embodiment proposed in this specification, there is anew effect of increasing transmission efficiency and throughput bysupporting aggregation of small-RUs of various sizes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a transmitting apparatus and/or receivingapparatus of the present specification.

FIG. 2 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

FIG. 3 illustrates a general link setup process.

FIG. 4 illustrates an example of a PPDU used in an IEEE standard.

FIG. 5 illustrates a layout of resource units (RUs) used in a band of 20MHz.

FIG. 6 illustrates a layout of RUs used in a band of 40 MHz.

FIG. 7 illustrates a layout of RUs used in a band of 80 MHz.

FIG. 8 illustrates a structure of an HE-SIG-B field.

FIG. 9 illustrates an example in which a plurality of user STAs areallocated to the same RU through an MU-MIMO scheme.

FIG. 10 illustrates an operation based on UL-MU.

FIG. 11 illustrates an example of a trigger frame.

FIG. 12 illustrates an example of a common information field of atrigger frame.

FIG. 13 illustrates an example of a subfield included in a per userinformation field.

FIG. 14 describes a technical feature of the UORA scheme.

FIG. 15 illustrates an example of a channel used/supported/definedwithin a 2.4 GHz band.

FIG. 16 illustrates an example of a channel used/supported/definedwithin a 5 GHz band.

FIG. 17 illustrates an example of a channel used/supported/definedwithin a 6 GHz band.

FIG. 18 illustrates an example of a PPDU used in the presentspecification.

FIG. 19 illustrates an example of a modified transmission device and/orreceiving apparatus/device of the present specification.

FIG. 20 shows an example of a PHY transmission procedure for HE SU PPDU.

FIG. 21 shows an example of a block diagram of a transmitting device forgenerating each field of an HE PPDU.

FIG. 22 shows an example of an 80 MHz tone plan in which 20 MHzpuncturing is performed.

FIG. 23 shows an example of an EHT PPDU format.

FIG. 24 shows an example of a U-SIG format.

FIG. 25 is a flowchart illustrating the operation of the transmittingapparatus according to the present embodiment.

FIG. 26 is a flowchart illustrating the operation of the receivingapparatus according to the present embodiment.

FIG. 27 is a flowchart illustrating a procedure in which a transmittingSTA transmits a PPDU according to the present embodiment.

FIG. 28 is a flowchart illustrating a procedure for a receiving STA toreceive a PPDU according to the present embodiment.

DETAILED DESCRIPTION

In the present specification, “A or B” may mean “only A”, “only B” or“both A and B”. In other words, in the present specification, “A or B”may be interpreted as “A and/or B”. For example, in the presentspecification, “A, B, or C” may mean “only A”, “only B”, “only C”, or“any combination of A, B, C”.

A slash (/) or comma used in the present specification may mean“and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B”may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C”may mean “A, B, or C”.

In the present specification, “at least one of A and B” may mean “onlyA”, “only B”, or “both A and B”. In addition, in the presentspecification, the expression “at least one of A or B” or “at least oneof A and/or B” may be interpreted as “at least one of A and B”.

In addition, in the present specification, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present specification may mean“for example”. Specifically, when indicated as “control information(EHT-signal)”, it may denote that “EHT-signal” is proposed as an exampleof the “control information”. In other words, the “control information”of the present specification is not limited to “EHT-signal”, and“EHT-signal” may be proposed as an example of the “control information”.In addition, when indicated as “control information (i.e., EHT-signal)”,it may also mean that “EHT-signal” is proposed as an example of the“control information”.

Technical features described individually in one figure in the presentspecification may be individually implemented, or may be simultaneouslyimplemented.

The following example of the present specification may be applied tovarious wireless communication systems. For example, the followingexample of the present specification may be applied to a wireless localarea network (WLAN) system. For example, the present specification maybe applied to the IEEE 802.11a/g/n/ac standard or the IEEE 802.11axstandard. In addition, the present specification may also be applied tothe newly proposed EHT standard or IEEE 802.11be standard. In addition,the example of the present specification may also be applied to a newWLAN standard enhanced from the EHT standard or the IEEE 802.11bestandard. In addition, the example of the present specification may beapplied to a mobile communication system. For example, it may be appliedto a mobile communication system based on long term evolution (LTE)depending on a 3^(rd) generation partnership project (3GPP) standard andbased on evolution of the LTE. In addition, the example of the presentspecification may be applied to a communication system of a 5G NRstandard based on the 3GPP standard.

Hereinafter, in order to describe a technical feature of the presentspecification, a technical feature applicable to the presentspecification will be described.

FIG. 1 shows an example of a transmitting apparatus and/or receivingapparatus of the present specification.

In the example of FIG. 1 , various technical features described belowmay be performed. FIG. 1 relates to at least one station (STA). Forexample, STAs 110 and 120 of the present specification may also becalled in various terms such as a mobile terminal, a wireless device, awireless transmit/receive unit (WTRU), a user equipment (UE), a mobilestation (MS), a mobile subscriber unit, or simply a user. The STAs 110and 120 of the present specification may also be called in various termssuch as a network, a base station, a node-B, an access point (AP), arepeater, a router, a relay, or the like. The STAs 110 and 120 of thepresent specification may also be referred to as various names such as areceiving apparatus, a transmitting apparatus, a receiving STA, atransmitting STA, a receiving device, a transmitting device, or thelike.

For example, the STAs 110 and 120 may serve as an AP or a non-AP. Thatis, the STAs 110 and 120 of the present specification may serve as theAP and/or the non-AP.

The STAs 110 and 120 of the present specification may support variouscommunication standards together in addition to the IEEE 802.11standard. For example, a communication standard (e.g., LTE, LTE-A, 5G NRstandard) or the like based on the 3GPP standard may be supported. Inaddition, the STA of the present specification may be implemented asvarious devices such as a mobile phone, a vehicle, a personal computer,or the like. In addition, the STA of the present specification maysupport communication for various communication services such as voicecalls, video calls, data communication, and self-driving(autonomous-driving), or the like.

The STAs 110 and 120 of the present specification may include a mediumaccess control (MAC) conforming to the IEEE 802.11 standard and aphysical layer interface for a radio medium.

The STAs 110 and 120 will be described below with reference to asub-figure (a) of FIG. 1 .

The first STA 110 may include a processor 111, a memory 112, and atransceiver 113. The illustrated process, memory, and transceiver may beimplemented individually as separate chips, or at least twoblocks/functions may be implemented through a single chip.

The transceiver 113 of the first STA performs a signaltransmission/reception operation. Specifically, an IEEE 802.11 packet(e.g., IEEE 802.11 a/b/g/n/ac/ax/be, etc.) may be transmitted/received.

For example, the first STA 110 may perform an operation intended by anAP. For example, the processor 111 of the AP may receive a signalthrough the transceiver 113, process a reception (RX) signal, generate atransmission (TX) signal, and provide control for signal transmission.The memory 112 of the AP may store a signal (e.g., RX signal) receivedthrough the transceiver 113, and may store a signal (e.g., TX signal) tobe transmitted through the transceiver.

For example, the second STA 120 may perform an operation intended by anon-AP STA. For example, a transceiver 123 of a non-AP performs a signaltransmission/reception operation. Specifically, an IEEE 802.11 packet(e.g., IEEE 802.11a/b/g/n/ac/ax/be packet, etc.) may betransmitted/received.

For example, a processor 121 of the non-AP STA may receive a signalthrough the transceiver 123, process an RX signal, generate a TX signal,and provide control for signal transmission. A memory 122 of the non-APSTA may store a signal (e.g., RX signal) received through thetransceiver 123, and may store a signal (e.g., TX signal) to betransmitted through the transceiver.

For example, an operation of a device indicated as an AP in thespecification described below may be performed in the first STA 110 orthe second STA 120. For example, if the first STA 110 is the AP, theoperation of the device indicated as the AP may be controlled by theprocessor 111 of the first STA 110, and a related signal may betransmitted or received through the transceiver 113 controlled by theprocessor 111 of the first STA 110. In addition, control informationrelated to the operation of the AP or a TX/RX signal of the AP may bestored in the memory 112 of the first STA 110. In addition, if thesecond STA 120 is the AP, the operation of the device indicated as theAP may be controlled by the processor 121 of the second STA 120, and arelated signal may be transmitted or received through the transceiver123 controlled by the processor 121 of the second STA 120. In addition,control information related to the operation of the AP or a TX/RX signalof the AP may be stored in the memory 122 of the second STA 120.

For example, in the specification described below, an operation of adevice indicated as a non-AP (or user-STA) may be performed in the firstSTA 110 or the second STA 120. For example, if the second STA 120 is thenon-AP, the operation of the device indicated as the non-AP may becontrolled by the processor 121 of the second STA 120, and a relatedsignal may be transmitted or received through the transceiver 123controlled by the processor 121 of the second STA 120. In addition,control information related to the operation of the non-AP or a TX/RXsignal of the non-AP may be stored in the memory 122 of the second STA120. For example, if the first STA 110 is the non-AP, the operation ofthe device indicated as the non-AP may be controlled by the processor111 of the first STA 110, and a related signal may be transmitted orreceived through the transceiver 113 controlled by the processor 111 ofthe first STA 110. In addition, control information related to theoperation of the non-AP or a TX/RX signal of the non-AP may be stored inthe memory 112 of the first STA 110.

In the specification described below, a device called a(transmitting/receiving) STA, a first STA, a second STA, a STA1, a STA2,an AP, a first AP, a second AP, an AP1, an AP2, a(transmitting/receiving) terminal, a (transmitting/receiving) device, a(transmitting/receiving) apparatus, a network, or the like may imply theSTAs 110 and 120 of FIG. 1 . For example, a device indicated as, withouta specific reference numeral, the (transmitting/receiving) STA, thefirst STA, the second STA, the STA1, the STA2, the AP, the first AP, thesecond AP, the AP1, the AP2, the (transmitting/receiving) terminal, the(transmitting/receiving) device, the (transmitting/receiving) apparatus,the network, or the like may imply the STAs 110 and 120 of FIG. 1 . Forexample, in the following example, an operation in which various STAstransmit/receive a signal (e.g., a PPDU) may be performed in thetransceivers 113 and 123 of FIG. 1 . In addition, in the followingexample, an operation in which various STAs generate a TX/RX signal orperform data processing and computation in advance for the TX/RX signalmay be performed in the processors 111 and 121 of FIG. 1 . For example,an example of an operation for generating the TX/RX signal or performingthe data processing and computation in advance may include: 1) anoperation ofdetermining/obtaining/configuring/computing/decoding/encoding bitinformation of a sub-field (SIG, STF, LTF, Data) included in a PPDU; 2)an operation of determining/configuring/obtaining a time resource orfrequency resource (e.g., a subcarrier resource) or the like used forthe sub-field (SIG, STF, LTF, Data) included the PPDU; 3) an operationof determining/configuring/obtaining a specific sequence (e.g., a pilotsequence, an STF/LTF sequence, an extra sequence applied to SIG) or thelike used for the sub-field (SIG, STF, LTF, Data) field included in thePPDU; 4) a power control operation and/or power saving operation appliedfor the STA; and 5) an operation related todetermining/obtaining/configuring/decoding/encoding or the like of anACK signal. In addition, in the following example, a variety ofinformation used by various STAs fordetermining/obtaining/configuring/computing/decoding/decoding a TX/RXsignal (e.g., information related to a field/subfield/controlfield/parameter/power or the like) may be stored in the memories 112 and122 of FIG. 1 .

The aforementioned device/STA of the sub-figure (a) of FIG. 1 may bemodified as shown in the sub-figure (b) of FIG. 1 . Hereinafter, theSTAs 110 and 120 of the present specification will be described based onthe sub-figure (b) of FIG. 1 .

For example, the transceivers 113 and 123 illustrated in the sub-figure(b) of FIG. 1 may perform the same function as the aforementionedtransceiver illustrated in the sub-figure (a) of FIG. 1 . For example,processing chips 114 and 124 illustrated in the sub-figure (b) of FIG. 1may include the processors 111 and 121 and the memories 112 and 122. Theprocessors 111 and 121 and memories 112 and 122 illustrated in thesub-figure (b) of FIG. 1 may perform the same function as theaforementioned processors 111 and 121 and memories 112 and 122illustrated in the sub-figure (a) of FIG. 1 .

A mobile terminal, a wireless device, a wireless transmit/receive unit(WTRU), a user equipment (UE), a mobile station (MS), a mobilesubscriber unit, a user, a user STA, a network, a base station, aNode-B, an access point (AP), a repeater, a router, a relay, a receivingunit, a transmitting unit, a receiving STA, a transmitting STA, areceiving device, a transmitting device, a receiving apparatus, and/or atransmitting apparatus, which are described below, may imply the STAs110 and 120 illustrated in the sub-figure (a)/(b) of FIG. 1 , or mayimply the processing chips 114 and 124 illustrated in the sub-figure (b)of FIG. 1 . That is, a technical feature of the present specificationmay be performed in the STAs 110 and 120 illustrated in the sub-figure(a)/(b) of FIG. 1 , or may be performed only in the processing chips 114and 124 illustrated in the sub-figure (b) of FIG. 1 . For example, atechnical feature in which the transmitting STA transmits a controlsignal may be understood as a technical feature in which a controlsignal generated in the processors 111 and 121 illustrated in thesub-figure (a)/(b) of FIG. 1 is transmitted through the transceivers 113and 123 illustrated in the sub-figure (a)/(b) of FIG. 1 . Alternatively,the technical feature in which the transmitting STA transmits thecontrol signal may be understood as a technical feature in which thecontrol signal to be transferred to the transceivers 113 and 123 isgenerated in the processing chips 114 and 124 illustrated in thesub-figure (b) of FIG. 1 .

For example, a technical feature in which the receiving STA receives thecontrol signal may be understood as a technical feature in which thecontrol signal is received by means of the transceivers 113 and 123illustrated in the sub-figure (a) of FIG. 1 . Alternatively, thetechnical feature in which the receiving STA receives the control signalmay be understood as the technical feature in which the control signalreceived in the transceivers 113 and 123 illustrated in the sub-figure(a) of FIG. 1 is obtained by the processors 111 and 121 illustrated inthe sub-figure (a) of FIG. 1 . Alternatively, the technical feature inwhich the receiving STA receives the control signal may be understood asthe technical feature in which the control signal received in thetransceivers 113 and 123 illustrated in the sub-figure (b) of FIG. 1 isobtained by the processing chips 114 and 124 illustrated in thesub-figure (b) of FIG. 1 .

Referring to the sub-figure (b) of FIG. 1 , software codes 115 and 125may be included in the memories 112 and 122. The software codes 115 and126 may include instructions for controlling an operation of theprocessors 111 and 121. The software codes 115 and 125 may be includedas various programming languages.

The processors 111 and 121 or processing chips 114 and 124 of FIG. 1 mayinclude an application-specific integrated circuit (ASIC), otherchipsets, a logic circuit and/or a data processing device. The processormay be an application processor (AP). For example, the processors 111and 121 or processing chips 114 and 124 of FIG. 1 may include at leastone of a digital signal processor (DSP), a central processing unit(CPU), a graphics processing unit (GPU), and a modulator and demodulator(modem). For example, the processors 111 and 121 or processing chips 114and 124 of FIG. 1 may be SNAPDRAGON™ series of processors made byQualcomm®, EXYNOS™ series of processors made by Samsung®, A series ofprocessors made by Apple®, HELIO™ series of processors made byMediaTek®, ATOM™ series of processors made by Intel® or processorsenhanced from these processors.

In the present specification, an uplink may imply a link forcommunication from a non-AP STA to an SP STA, and an uplinkPPDU/packet/signal or the like may be transmitted through the uplink. Inaddition, in the present specification, a downlink may imply a link forcommunication from the AP STA to the non-AP STA, and a downlinkPPDU/packet/signal or the like may be transmitted through the downlink.

FIG. 2 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

An upper part of FIG. 2 illustrates the structure of an infrastructurebasic service set (BSS) of institute of electrical and electronicengineers (IEEE) 802.11.

Referring the upper part of FIG. 2 , the wireless LAN system may includeone or more infrastructure BSSs 200 and 205 (hereinafter, referred to asBSS). The BSSs 200 and 205 as a set of an AP and a STA such as an accesspoint (AP) 225 and a station (STA1) 200-1 which are successfullysynchronized to communicate with each other are not concepts indicatinga specific region. The BSS 205 may include one or more STAs 205-1 and205-2 which may be joined to one AP 230.

The BSS may include at least one STA, APs providing a distributionservice, and a distribution system (DS) 210 connecting multiple APs.

The distribution system 210 may implement an extended service set (ESS)240 extended by connecting the multiple BSSs 200 and 205. The ESS 240may be used as a term indicating one network configured by connectingone or more APs 225 or 230 through the distribution system 210. The APincluded in one ESS 240 may have the same service set identification(SSID).

A portal 220 may serve as a bridge which connects the wireless LANnetwork (IEEE 802.11) and another network (e.g., 802.X).

In the BSS illustrated in the upper part of FIG. 2 , a network betweenthe APs 225 and 230 and a network between the APs 225 and 230 and theSTAs 200-1, 205-1, and 205-2 may be implemented. However, the network isconfigured even between the STAs without the APs 225 and 230 to performcommunication. A network in which the communication is performed byconfiguring the network even between the STAs without the APs 225 and230 is defined as an Ad-Hoc network or an independent basic service set(IBSS).

A lower part of FIG. 2 illustrates a conceptual view illustrating theIBSS.

Referring to the lower part of FIG. 2 , the IBSS is a BSS that operatesin an Ad-Hoc mode. Since the IBSS does not include the access point(AP), a centralized management entity that performs a managementfunction at the center does not exist. That is, in the IBSS, STAs 250-1,250-2, 250-3, 255-4, and 255-5 are managed by a distributed manner. Inthe IBSS, all STAs 250-1, 250-2, 250-3, 255-4, and 255-5 may beconstituted by movable STAs and are not permitted to access the DS toconstitute a self-contained network.

FIG. 3 illustrates a general link setup process.

In S310, a STA may perform a network discovery operation. The networkdiscovery operation may include a scanning operation of the STA. Thatis, to access a network, the STA needs to discover a participatingnetwork. The STA needs to identify a compatible network beforeparticipating in a wireless network, and a process of identifying anetwork present in a particular area is referred to as scanning.Scanning methods include active scanning and passive scanning.

FIG. 3 illustrates a network discovery operation including an activescanning process. In active scanning, a STA performing scanningtransmits a probe request frame and waits for a response to the proberequest frame in order to identify which AP is present around whilemoving to channels. A responder transmits a probe response frame as aresponse to the probe request frame to the STA having transmitted theprobe request frame. Here, the responder may be a STA that transmits thelast beacon frame in a BSS of a channel being scanned. In the BSS, sincean AP transmits a beacon frame, the AP is the responder. In an IBSS,since STAs in the IBSS transmit a beacon frame in turns, the responderis not fixed. For example, when the STA transmits a probe request framevia channel 1 and receives a probe response frame via channel 1, the STAmay store BSS-related information included in the received proberesponse frame, may move to the next channel (e.g., channel 2), and mayperform scanning (e.g., transmits a probe request and receives a proberesponse via channel 2) by the same method.

Although not shown in FIG. 3 , scanning may be performed by a passivescanning method. In passive scanning, a STA performing scanning may waitfor a beacon frame while moving to channels. A beacon frame is one ofmanagement frames in IEEE 802.11 and is periodically transmitted toindicate the presence of a wireless network and to enable the STAperforming scanning to find the wireless network and to participate inthe wireless network. In a BSS, an AP serves to periodically transmit abeacon frame. In an IBSS, STAs in the IBSS transmit a beacon frame inturns. Upon receiving the beacon frame, the STA performing scanningstores information related to a BSS included in the beacon frame andrecords beacon frame information in each channel while moving to anotherchannel. The STA having received the beacon frame may store BSS-relatedinformation included in the received beacon frame, may move to the nextchannel, and may perform scanning in the next channel by the samemethod.

After discovering the network, the STA may perform an authenticationprocess in S320. The authentication process may be referred to as afirst authentication process to be clearly distinguished from thefollowing security setup operation in S340. The authentication processin S320 may include a process in which the STA transmits anauthentication request frame to the AP and the AP transmits anauthentication response frame to the STA in response. The authenticationframes used for an authentication request/response are managementframes.

The authentication frames may include information related to anauthentication algorithm number, an authentication transaction sequencenumber, a status code, a challenge text, a robust security network(RSN), and a finite cyclic group.

The STA may transmit the authentication request frame to the AP. The APmay determine whether to allow the authentication of the STA based onthe information included in the received authentication request frame.The AP may provide the authentication processing result to the STA viathe authentication response frame.

When the STA is successfully authenticated, the STA may perform anassociation process in S330. The association process includes a processin which the STA transmits an association request frame to the AP andthe AP transmits an association response frame to the STA in response.The association request frame may include, for example, informationrelated to various capabilities, a beacon listen interval, a service setidentifier (SSID), a supported rate, a supported channel, RSN, amobility domain, a supported operating class, a traffic indication map(TIM) broadcast request, and an interworking service capability. Theassociation response frame may include, for example, information relatedto various capabilities, a status code, an association ID (AID), asupported rate, an enhanced distributed channel access (EDCA) parameterset, a received channel power indicator (RCPI), a receivedsignal-to-noise indicator (RSNI), a mobility domain, a timeout interval(association comeback time), an overlapping BSS scanning parameter, aTIM broadcast response, and a QoS map.

In S340, the STA may perform a security setup process. The securitysetup process in S340 may include a process of setting up a private keythrough four-way handshaking, for example, through an extensibleauthentication protocol over LAN (EAPOL) frame.

FIG. 4 illustrates an example of a PPDU used in an IEEE standard.

As illustrated, various types of PHY protocol data units (PPDUs) areused in IEEE a/g/n/ac standards. Specifically, an LTF and a STF includea training signal, a SIG-A and a SIG-B include control information for areceiving STA, and a data field includes user data corresponding to aPSDU (MAC PDU/aggregated MAC PDU).

FIG. 4 also includes an example of an HE PPDU according to IEEE802.11ax. The HE PPDU according to FIG. 4 is an illustrative PPDU formultiple users. An HE-SIG-B may be included only in a PPDU for multipleusers, and an HE-SIG-B may be omitted in a PPDU for a single user.

As illustrated in FIG. 4 , the HE-PPDU for multiple users (MUs) mayinclude a legacy-short training field (L-STF), a legacy-long trainingfield (L-LTF), a legacy-signal (L-SIG), a high efficiency-signal A(HE-SIG A), a high efficiency-signal-B (HE-SIG B), a highefficiency-short training field (HE-STF), a high efficiency-longtraining field (HE-LTF), a data field (alternatively, an MAC payload),and a packet extension (PE) field. The respective fields may betransmitted for illustrated time periods (i.e., 4 or 8 μs).

Hereinafter, a resource unit (RU) used for a PPDU is described. An RUmay include a plurality of subcarriers (or tones). An RU may be used totransmit a signal to a plurality of STAs according to OFDMA. Further, anRU may also be defined to transmit a signal to one STA. An RU may beused for an STF, an LTF, a data field, or the like.

FIG. 5 illustrates a layout of resource units (RUs) used in a band of 20MHz.

As illustrated in FIG. 5 , resource units (RUs) corresponding todifferent numbers of tones (i.e., subcarriers) may be used to form somefields of an HE-PPDU. For example, resources may be allocated inillustrated RUs for an HE-STF, an HE-LTF, and a data field.

As illustrated in the uppermost part of FIG. 5 , a 26-unit (i.e., a unitcorresponding to 26 tones) may be disposed. Six tones may be used for aguard band in the leftmost band of the 20 MHz band, and five tones maybe used for a guard band in the rightmost band of the 20 MHz band.Further, seven DC tones may be inserted in a center band, that is, a DCband, and a 26-unit corresponding to 13 tones on each of the left andright sides of the DC band may be disposed. A 26-unit, a 52-unit, and a106-unit may be allocated to other bands. Each unit may be allocated fora receiving STA, that is, a user.

The layout of the RUs in FIG. 5 may be used not only for a multipleusers (MUs) but also for a single user (SU), in which case one 242-unitmay be used and three DC tones may be inserted as illustrated in thelowermost part of FIG. 5 .

Although FIG. 5 proposes RUs having various sizes, that is, a 26-RU, a52-RU, a 106-RU, and a 242-RU, specific sizes of RUs may be extended orincreased. Therefore, the present embodiment is not limited to thespecific size of each RU (i.e., the number of corresponding tones).

FIG. 6 illustrates a layout of RUs used in a band of 40 MHz.

Similarly to FIG. 5 in which RUs having various sizes are used, a 26-RU,a 52-RU, a 106-RU, a 242-RU, a 484-RU, and the like may be used in anexample of FIG. 6 . Further, five DC tones may be inserted in a centerfrequency, 12 tones may be used for a guard band in the leftmost band ofthe 40 MHz band, and 11 tones may be used for a guard band in therightmost band of the 40 MHz band.

As illustrated in FIG. 6 , when the layout of the RUs is used for asingle user, a 484-RU may be used. The specific number of RUs may bechanged similarly to FIG. 5 .

FIG. 7 illustrates a layout of RUs used in a band of 80 MHz.

Similarly to FIG. 5 and FIG. 6 in which RUs having various sizes areused, a 26-RU, a 52-RU, a 106-RU, a 242-RU, a 484-RU, a 996-RU, and thelike may be used in an example of FIG. 7 . Further, seven DC tones maybe inserted in the center frequency, 12 tones may be used for a guardband in the leftmost band of the 80 MHz band, and 11 tones may be usedfor a guard band in the rightmost band of the 80 MHz band. In addition,a 26-RU corresponding to 13 tones on each of the left and right sides ofthe DC band may be used.

As illustrated in FIG. 7 , when the layout of the RUs is used for asingle user, a 996-RU may be used, in which case five DC tones may beinserted.

The RU described in the present specification may be used in uplink (UL)communication and downlink (DL) communication. For example, when UL-MUcommunication which is solicited by a trigger frame is performed, atransmitting STA (e.g., an AP) may allocate a first RU (e.g.,26/52/106/242-RU, etc.) to a first STA through the trigger frame, andmay allocate a second RU (e.g., 26/52/106/242-RU, etc.) to a second STA.Thereafter, the first STA may transmit a first trigger-based PPDU basedon the first RU, and the second STA may transmit a second trigger-basedPPDU based on the second RU. The first/second trigger-based PPDU istransmitted to the AP at the same (or overlapped) time period.

For example, when a DL MU PPDU is configured, the transmitting STA(e.g., AP) may allocate the first RU (e.g., 26/52/106/242-RU. etc.) tothe first STA, and may allocate the second RU (e.g., 26/52/106/242-RU,etc.) to the second STA. That is, the transmitting STA (e.g., AP) maytransmit HE-STF, HE-LTF, and Data fields for the first STA through thefirst RU in one MU PPDU, and may transmit HE-STF, HE-LTF, and Datafields for the second STA through the second RU.

Information related to a layout of the RU may be signaled throughHE-SIG-B.

FIG. 8 illustrates a structure of an HE-SIG-B field.

As illustrated, an HE-SIG-B field 810 includes a common field 820 and auser-specific field 830. The common field 820 may include informationcommonly applied to all users (i.e., user STAs) which receive SIG-B. Theuser-specific field 830 may be called a user-specific control field.When the SIG-B is transferred to a plurality of users, the user-specificfield 830 may be applied only any one of the plurality of users.

As illustrated in FIG. 8 , the common field 820 and the user-specificfield 830 may be separately encoded.

The common field 820 may include RU allocation information of N*8 bits.For example, the RU allocation information may include informationrelated to a location of an RU. For example, when a 20 MHz channel isused as shown in FIG. 5 , the RU allocation information may includeinformation related to a specific frequency band to which a specific RU(26-RU/52-RU/106-RU) is arranged.

An example of a case in which the RU allocation information consists of8 bits is as follows.

TABLE 1 8 bits indices (B7 B6 B5 B4 Number B3 B2 B1 B0) #1 #2 #3 #4 #5#6 #7 #8 #9 of entries 00000000 26 26 26 26 26 26 26 26 26 1 00000001 2626 26 26 26 26 26 52 1 00000010 26 26 26 26 26 52 26 26 1 00000011 26 2626 26 26 52 52 1 00000100 26 26 52 26 26 26 26 26 1 00000101 26 26 52 2626 26 52 1 00000110 26 26 52 26 52 26 26 1 00000111 26 26 52 26 52 52 100001000 52 26 26 26 26 26 26 26 1

As shown the example of FIG. 5 , up to nine 26-RUs may be allocated tothe 20 MHz channel. When the RU allocation information of the commonfield 820 is set to “00000000” as shown in Table 1, the nine 26-RUs maybe allocated to a corresponding channel (i.e., 20 MHz). In addition,when the RU allocation information of the common field 820 is set to“00000001” as shown in Table 1, seven 26-RUs and one 52-RU are arrangedin a corresponding channel. That is, in the example of FIG. 5 , the52-RU may be allocated to the rightmost side, and the seven 26-RUs maybe allocated to the left thereof.

The example of Table 1 shows only some of RU locations capable ofdisplaying the RU allocation information.

For example, the RU allocation information may include an example ofTable 2 below.

TABLE 2 8 bits indices (B7 B6 B5 B4 Number B3 B2 B1 B0) #1 #2 #3 #4 #5#6 #7 #8 #9 of entries 01000y₂y₁y₀ 106 26 26 26 26 26 8 01001y₂y₁y₀ 10626 26 26 52 8

“01000y2y1y0” relates to an example in which a 106-RU is allocated tothe leftmost side of the 20 MHz channel, and five 26-RUs are allocatedto the right side thereof. In this case, a plurality of STAs (e.g.,user-STAs) may be allocated to the 106-RU, based on an MU-MIMO scheme.Specifically, up to 8 STAs (e.g., user-STAs) may be allocated to the106-RU, and the number of STAs (e.g., user-STAs) allocated to the 106-RUis determined based on 3-bit information (y2y1y0). For example, when the3-bit information (y2y1y0) is set to N, the number of STAs (e.g.,user-STAs) allocated to the 106-RU based on the MU-MIMO scheme may beN+1.

In general, a plurality of STAs (e.g., user STAs) different from eachother may be allocated to a plurality of RUs. However, the plurality ofSTAs (e.g., user STAs) may be allocated to one or more RUs having atleast a specific size (e.g., 106 subcarriers), based on the MU-MIMOscheme.

As shown in FIG. 8 , the user-specific field 830 may include a pluralityof user fields. As described above, the number of STAs (e.g., user STAs)allocated to a specific channel may be determined based on the RUallocation information of the common field 820. For example, when the RUallocation information of the common field 820 is “00000000”, one userSTA may be allocated to each of nine 26-RUs (e.g., nine user STAs may beallocated). That is, up to 9 user STAs may be allocated to a specificchannel through an OFDMA scheme. In other words, up to 9 user STAs maybe allocated to a specific channel through a non-MU-MIMO scheme.

For example, when RU allocation is set to “01000y2y1y0”, a plurality ofSTAs may be allocated to the 106-RU arranged at the leftmost sidethrough the MU-MIMO scheme, and five user STAs may be allocated to five26-RUs arranged to the right side thereof through the non-MU MIMOscheme. This case is specified through an example of FIG. 9 .

FIG. 9 illustrates an example in which a plurality of user STAs areallocated to the same RU through an MU-MIMO scheme.

For example, when RU allocation is set to “01000010” as shown in FIG. 9, a 106-RU may be allocated to the leftmost side of a specific channel,and five 26-RUs may be allocated to the right side thereof. In addition,three user STAs may be allocated to the 106-RU through the MU-MIMOscheme. As a result, since eight user STAs are allocated, theuser-specific field 830 of HE-SIG-B may include eight user fields.

The eight user fields may be expressed in the order shown in FIG. 9 . Inaddition, as shown in FIG. 8 , two user fields may be implemented withone user block field.

The user fields shown in FIG. 8 and FIG. 9 may be configured based ontwo formats. That is, a user field related to an MU-MIMO scheme may beconfigured in a first format, and a user field related to a non-MIMOscheme may be configured in a second format. Referring to the example ofFIG. 9 , a user field 1 to a user field 3 may be based on the firstformat, and a user field 4 to a user field 8 may be based on the secondformat. The first format or the second format may include bitinformation of the same length (e.g., 21 bits).

Each user field may have the same size (e.g., 21 bits). For example, theuser field of the first format (the first of the MU-MIMO scheme) may beconfigured as follows.

For example, a first bit (i.e., B0-B10) in the user field (i.e., 21bits) may include identification information (e.g., STA-ID, partial AID,etc.) of a user STA to which a corresponding user field is allocated. Inaddition, a second bit (i.e., B11-B14) in the user field (i.e., 21 bits)may include information related to a spatial configuration.Specifically, an example of the second bit (i.e., B11-B14) may be asshown in Table 3 and Table 4 below.

TABLE 3 N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS)Total Number N_(user) B3 . . . B0 [1] [2] [3] [4] [5] [6] [7] [8]N_(STS) of entries 2 0000-0011 1-4 1 2-5 10 0100-0110 2-4 2 4-60111-1000 3-4 3 6-7 1001 4 4 8 3 0000-0011 1-4 1 1 3-6 13 0100-0110 2-42 1 5-7 0111-1000 3-4 3 1 7-8 1001-1011 2-4 2 2 6-8 1100 3 3 2 8 40000-0011 1-4 1 1 1 4-7 11 0100-0110 2-4 2 1 1 6-8 0111 3 3 1 1 81000-1001 2-3 2 2 1 7-8 1010 2 2 2 2 8

TABLE 4 N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS)Total Number N_(user) B3 . . . B0 [1] [2] [3] [4] [5] [6] [7] [8]N_(STS) of entries 5 0000-0011 1-4 1 1 1 1 5-8 7 0100-0101 2-3 2 1 1 17-8 0110 2 2 2 1 1 8 6 0000-0010 1-3 1 1 1 1 1 6-8 4 0011 2 2 1 1 1 1 87 0000-0001 1-2 1 1 1 1 1 1 7-8 2 8 0000 1 1 1 1 1 1 1 1 8 1

As shown in Table 3 and/or Table 4, the second bit (e.g. B11-B14) mayinclude information related to the number of spatial streams allocatedto the plurality of user STAs which are allocated based on the MU-MIMOscheme. For example, when three user STAs are allocated to the 106-RUbased on the MU-MIMO scheme as shown in FIG. 9 , N_user is set to “3”.Therefore, values of N_STS[1], N_STS[2], and N_STS[3] may be determinedas shown in Table 3. For example, when a value of the second bit(B11-B14) is “0011”, it may be set to N_STS[1]=4, N_STS[2]=1,N_STS[3]=1. That is, in the example of FIG. 9 , four spatial streams maybe allocated to the user field 1, one spatial stream may be allocated tothe user field 1, and one spatial stream may be allocated to the userfield 3.

As shown in the example of Table 3 and/or Table 4, information (i.e.,the second bit, B11-B14) related to the number of spatial streams forthe user STA may consist of 4 bits. In addition, the information (i.e.,the second bit, B11-B14) on the number of spatial streams for the userSTA may support up to eight spatial streams. In addition, theinformation (i.e., the second bit, B111-B14) on the number of spatialstreams for the user STA may support up to four spatial streams for oneuser STA.

In addition, a third bit (i.e., B15-18) in the user field (i.e., 21bits) may include modulation and coding scheme (MCS) information. TheMCS information may be applied to a data field in a PPDU includingcorresponding SIG-B.

An MCS, MCS information, an MCS index, an MCS field, or the like used inthe present specification may be indicated by an index value. Forexample, the MCS information may be indicated by an index 0 to an index11. The MCS information may include information related to aconstellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM,256-QAM, 1024-QAM, etc.) and information related to a coding rate (e.g.,1/2, 2/3, 3/4, 5/6e, etc.). Information related to a channel coding type(e.g., LCC or LDPC) may be excluded in the MCS information.

In addition, a fourth bit (i.e., B19) in the user field (i.e., 21 bits)may be a reserved field.

In addition, a fifth bit (i.e., B20) in the user field (i.e., 21 bits)may include information related to a coding type (e.g., BCC or LDPC).That is, the fifth bit (i.e., B20) may include information related to atype (e.g., BCC or LDPC) of channel coding applied to the data field inthe PPDU including the corresponding SIG-B.

The aforementioned example relates to the user field of the first format(the format of the MU-MIMO scheme). An example of the user field of thesecond format (the format of the non-MU-MIMO scheme) is as follows.

A first bit (e.g., B0-B10) in the user field of the second format mayinclude identification information of a user STA. In addition, a secondbit (e.g., B11-B13) in the user field of the second format may includeinformation related to the number of spatial streams applied to acorresponding RU. In addition, a third bit (e.g., B14) in the user fieldof the second format may include information related to whether abeamforming steering matrix is applied. A fourth bit (e.g., B15-B18) inthe user field of the second format may include modulation and codingscheme (MCS) information. In addition, a fifth bit (e.g., B19) in theuser field of the second format may include information related towhether dual carrier modulation (DCM) is applied. In addition, a sixthbit (i.e., B20) in the user field of the second format may includeinformation related to a coding type (e.g., BCC or LDPC).

FIG. 10 illustrates an operation based on UL-MU. As illustrated, atransmitting STA (e.g., an AP) may perform channel access throughcontending (e.g., a backoff operation), and may transmit a trigger frame1030. That is, the transmitting STA may transmit a PPDU including thetrigger frame 1030. Upon receiving the PPDU including the trigger frame,a trigger-based (TB) PPDU is transmitted after a delay corresponding toSIFS.

TB PPDUs 1041 and 1042 may be transmitted at the same time period, andmay be transmitted from a plurality of STAs (e.g., user STAs) havingAIDs indicated in the trigger frame 1030. An ACK frame 1050 for the TBPPDU may be implemented in various forms.

A specific feature of the trigger frame is described with reference toFIG. 11 to FIG. 13 . Even if UL-MU communication is used, an orthogonalfrequency division multiple access (OFDMA) scheme or an MU MIMO schememay be used, and the OFDMA and MU-MIMO schemes may be simultaneouslyused.

FIG. 11 illustrates an example of a trigger frame. The trigger frame ofFIG. 11 allocates a resource for uplink multiple-user (MU) transmission,and may be transmitted, for example, from an AP. The trigger frame maybe configured of a MAC frame, and may be included in a PPDU.

Each field shown in FIG. 11 may be partially omitted, and another fieldmay be added. In addition, a length of each field may be changed to bedifferent from that shown in the figure.

A frame control field 1110 of FIG. 11 may include information related toa MAC protocol version and extra additional control information. Aduration field 1120 may include time information for NAV configurationor information related to an identifier (e.g., AID) of a STA.

In addition, an RA field 1130 may include address information of areceiving STA of a corresponding trigger frame, and may be optionallyomitted. A TA field 1140 may include address information of a STA (e.g.,an AP) which transmits the corresponding trigger frame. A commoninformation field 1150 includes common control information applied tothe receiving STA which receives the corresponding trigger frame. Forexample, a field indicating a length of an L-SIG field of an uplink PPDUtransmitted in response to the corresponding trigger frame orinformation for controlling content of a SIG-A field (i.e., HE-SIG-Afield) of the uplink PPDU transmitted in response to the correspondingtrigger frame may be included. In addition, as common controlinformation, information related to a length of a CP of the uplink PPDUtransmitted in response to the corresponding trigger frame orinformation related to a length of an LTF field may be included.

In addition, per user information fields 1160 #1 to 1160 #Ncorresponding to the number of receiving STAs which receive the triggerframe of FIG. 11 are preferably included. The per user information fieldmay also be called an “allocation field”.

In addition, the trigger frame of FIG. 11 may include a padding field1170 and a frame check sequence field 1180.

Each of the per user information fields 1160 #1 to 1160 #N shown in FIG.11 may include a plurality of subfields.

FIG. 12 illustrates an example of a common information field of atrigger frame. A subfield of FIG. 12 may be partially omitted, and anextra subfield may be added. In addition, a length of each subfieldillustrated may be changed.

A length field 1210 illustrated has the same value as a length field ofan L-SIG field of an uplink PPDU transmitted in response to acorresponding trigger frame, and a length field of the L-SIG field ofthe uplink PPDU indicates a length of the uplink PPDU. As a result, thelength field 1210 of the trigger frame may be used to indicate thelength of the corresponding uplink PPDU.

In addition, a cascade identifier field 1220 indicates whether a cascadeoperation is performed. The cascade operation implies that downlink MUtransmission and uplink MU transmission are performed together in thesame TXOP. That is, it implies that downlink MU transmission isperformed and thereafter uplink MU transmission is performed after apre-set time (e.g., SIFS). During the cascade operation, only onetransmitting device (e.g., AP) may perform downlink communication, and aplurality of transmitting devices (e.g., non-APs) may perform uplinkcommunication.

A CS request field 1230 indicates whether a wireless medium state or aNAV or the like is necessarily considered in a situation where areceiving device which has received a corresponding trigger frametransmits a corresponding uplink PPDU.

An HE-SIG-A information field 1240 may include information forcontrolling content of a SIG-A field (i.e., HE-SIG-A field) of theuplink PPDU in response to the corresponding trigger frame.

A CP and LTF type field 1250 may include information related to a CPlength and LTF length of the uplink PPDU transmitted in response to thecorresponding trigger frame. A trigger type field 1260 may indicate apurpose of using the corresponding trigger frame, for example, typicaltriggering, triggering for beamforming, a request for block ACK/NACK, orthe like.

It may be assumed that the trigger type field 1260 of the trigger framein the present specification indicates a trigger frame of a basic typefor typical triggering. For example, the trigger frame of the basic typemay be referred to as a basic trigger frame.

FIG. 13 illustrates an example of a subfield included in a per userinformation field. A user information field 1300 of FIG. 13 may beunderstood as any one of the per user information fields 1160 #1 to 1160#N mentioned above with reference to FIG. 11 . A subfield included inthe user information field 1300 of FIG. 13 may be partially omitted, andan extra subfield may be added. In addition, a length of each subfieldillustrated may be changed.

A user identifier field 1310 of FIG. 13 indicates an identifier of a STA(i.e., receiving STA) corresponding to per user information. An exampleof the identifier may be the entirety or part of an associationidentifier (AID) value of the receiving STA.

In addition, an RU allocation field 1320 may be included. That is, whenthe receiving STA identified through the user identifier field 1310transmits a TB PPDU in response to the trigger frame, the TB PPDU istransmitted through an RU indicated by the RU allocation field 1320. Inthis case, the RU indicated by the RU allocation field 1320 may be an RUshown in FIG. 5 , FIG. 6 , and FIG. 7 .

The subfield of FIG. 13 may include a coding type field 1330. The codingtype field 1330 may indicate a coding type of the TB PPDU. For example,when BCC coding is applied to the TB PPDU, the coding type field 1330may be set to ‘1’, and when LDPC coding is applied, the coding typefield 1330 may be set to ‘0’.

In addition, the subfield of FIG. 13 may include an MCS field 1340. TheMCS field 1340 may indicate an MCS scheme applied to the TB PPDU. Forexample, when BCC coding is applied to the TB PPDU, the coding typefield 1330 may be set to ‘1’, and when LDPC coding is applied, thecoding type field 1330 may be set to ‘0’.

Hereinafter, a UL OFDMA-based random access (UORA) scheme will bedescribed.

FIG. 14 describes a technical feature of the UORA scheme.

A transmitting STA (e.g., an AP) may allocate six RU resources through atrigger frame as shown in FIG. 14 . Specifically, the AP may allocate a1st RU resource (AID 0, RU 1), a 2nd RU resource (AID 0, RU 2), a 3rd RUresource (AID 0, RU 3), a 4th RU resource (AID 2045, RU 4), a 5th RUresource (AID 2045, RU 5), and a 6th RU resource (AID 3, RU 6).Information related to the AID 0, AID 3, or AID 2045 may be included,for example, in the user identifier field 1310 of FIG. 13 . Informationrelated to the RU 1 to RU 6 may be included, for example, in the RUallocation field 1320 of FIG. 13 . AID=0 may imply a UORA resource foran associated STA, and AID=2045 may imply a UORA resource for anun-associated STA. Accordingly, the 1st to 3rd RU resources of FIG. 14may be used as a UORA resource for the associated STA, the 4th and 5thRU resources of FIG. 14 may be used as a UORA resource for theun-associated STA, and the 6th RU resource of FIG. 14 may be used as atypical resource for UL MU.

In the example of FIG. 14 , an OFDMA random access backoff (OBO) of aSTA1 is decreased to 0, and the STA1 randomly selects the 2nd RUresource (AID 0, RU 2). In addition, since an OBO counter of a STA2/3 isgreater than 0, an uplink resource is not allocated to the STA2/3. Inaddition, regarding a STA4 in FIG. 14 , since an AID (e.g., AID=3) ofthe STA4 is included in a trigger frame, a resource of the RU 6 isallocated without backoff.

Specifically, since the STA1 of FIG. 14 is an associated STA, the totalnumber of eligible RA RUs for the STA1 is 3 (RU 1, RU 2, and RU 3), andthus the STA1 decreases an OBO counter by 3 so that the OBO counterbecomes 0. In addition, since the STA2 of FIG. 14 is an associated STA,the total number of eligible RA RUs for the STA2 is 3 (RU 1, RU 2, andRU 3), and thus the STA2 decreases the OBO counter by 3 but the OBOcounter is greater than 0. In addition, since the STA3 of FIG. 14 is anun-associated STA, the total number of eligible RA RUs for the STA3 is 2(RU 4, RU 5), and thus the STA3 decreases the OBO counter by 2 but theOBO counter is greater than 0.

FIG. 15 illustrates an example of a channel used/supported/definedwithin a 2.4 GHz band.

The 2.4 GHz band may be called in other terms such as a first band. Inaddition, the 2.4 GHz band may imply a frequency domain in whichchannels of which a center frequency is close to 2.4 GHz (e.g., channelsof which a center frequency is located within 2.4 to 2.5 GHz) areused/supported/defined.

A plurality of 20 MHz channels may be included in the 2.4 GHz band. 20MHz within the 2.4 GHz may have a plurality of channel indices (e.g., anindex 1 to an index 14). For example, a center frequency of a 20 MHzchannel to which a channel index 1 is allocated may be 2.412 GHz, acenter frequency of a 20 MHz channel to which a channel index 2 isallocated may be 2.417 GHz, and a center frequency of a 20 MHz channelto which a channel index N is allocated may be (2.407+0.005*N) GHz. Thechannel index may be called in various terms such as a channel number orthe like. Specific numerical values of the channel index and centerfrequency may be changed.

FIG. 15 exemplifies 4 channels within a 2.4 GHz band. Each of 1st to 4thfrequency domains 1510 to 1540 shown herein may include one channel. Forexample, the 1st frequency domain 1510 may include a channel 1 (a 20 MHzchannel having an index 1). In this case, a center frequency of thechannel 1 may be set to 2412 MHz. The 2nd frequency domain 1520 mayinclude a channel 6. In this case, a center frequency of the channel 6may be set to 2437 MHz. The 3rd frequency domain 1530 may include achannel 11. In this case, a center frequency of the channel 11 may beset to 2462 MHz. The 4th frequency domain 1540 may include a channel 14.In this case, a center frequency of the channel 14 may be set to 2484MHz.

FIG. 16 illustrates an example of a channel used/supported/definedwithin a 5 GHz band.

The 5 GHz band may be called in other terms such as a second band or thelike. The 5 GHz band may imply a frequency domain in which channels ofwhich a center frequency is greater than or equal to 5 GHz and less than6 GHz (or less than 5.9 GHz) are used/supported/defined. Alternatively,the 5 GHz band may include a plurality of channels between 4.5 GHz and5.5 GHz. A specific numerical value shown in FIG. 16 may be changed.

A plurality of channels within the 5 GHz band include an unlicensednational information infrastructure (UNII)-1, a UNII-2, a UNII-3, and anISM. The INII-1 may be called UNII Low. The UNII-2 may include afrequency domain called UNII Mid and UNII-2Extended. The UNII-3 may becalled UNII-Upper.

A plurality of channels may be configured within the 5 GHz band, and abandwidth of each channel may be variously set to, for example, 20 MHz,40 MHz, 80 MHz, 160 MHz, or the like. For example, 5170 MHz to 5330 MHzfrequency domains/ranges within the UNII-1 and UNII-2 may be dividedinto eight 20 MHz channels. The 5170 MHz to 5330 MHz frequencydomains/ranges may be divided into four channels through a 40 MHzfrequency domain. The 5170 MHz to 5330 MHz frequency domains/ranges maybe divided into two channels through an 80 MHz frequency domain.Alternatively, the 5170 MHz to 5330 MHz frequency domains/ranges may bedivided into one channel through a 160 MHz frequency domain.

FIG. 17 illustrates an example of a channel used/supported/definedwithin a 6 GHz band.

The 6 GHz band may be called in other terms such as a third band or thelike. The 6 GHz band may imply a frequency domain in which channels ofwhich a center frequency is greater than or equal to 5.9 GHz areused/supported/defined. A specific numerical value shown in FIG. 17 maybe changed.

For example, the 20 MHz channel of FIG. 17 may be defined starting from5.940 GHz. Specifically, among 20 MHz channels of FIG. 17 , the leftmostchannel may have an index 1 (or a channel index, a channel number,etc.), and 5.945 GHz may be assigned as a center frequency. That is, acenter frequency of a channel of an index N may be determined as(5.940+0.005*N) GHz.

Accordingly, an index (or channel number) of the 2 MHz channel of FIG.17 may be 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61,65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125,129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 173, 177, 181,185, 189, 193, 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. Inaddition, according to the aforementioned (5.940+0.005*N)GHz rule, anindex of the 40 MHz channel of FIG. 17 may be 3, 11, 19, 27, 35, 43, 51,59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171,179, 187, 195, 203, 211, 219, 227.

Although 20, 40, 80, and 160 MHz channels are illustrated in the exampleof FIG. 17 , a 240 MHz channel or a 320 MHz channel may be additionallyadded.

Hereinafter, a PPDU transmitted/received in a STA of the presentspecification will be described.

FIG. 18 illustrates an example of a PPDU used in the presentspecification.

The PPDU of FIG. 18 may be called in various terms such as an EHT PPDU,a TX PPDU, an RX PPDU, a first type or N-th type PPDU, or the like. Forexample, in the present specification, the PPDU or the EHT PPDU may becalled in various terms such as a TX PPDU, a RX PPDU, a first type orN-th type PPDU, or the like. In addition, the EHT PPDU may be used in anEHT system and/or a new WLAN system enhanced from the EHT system.

The PPDU of FIG. 18 may indicate the entirety or part of a PPDU typeused in the EHT system. For example, the example of FIG. 18 may be usedfor both of a single-user (SU) mode and a multi-user (MU) mode. In otherwords, the PPDU of FIG. 18 may be a PPDU for one receiving STA or aplurality of receiving STAs. When the PPDU of FIG. 18 is used for atrigger-based (TB) mode, the EHT-SIG of FIG. 18 may be omitted. In otherwords, an STA which has received a trigger frame for uplink-MU (UL-MU)may transmit the PPDU in which the EHT-SIG is omitted in the example ofFIG. 18 .

In FIG. 18 , an L-STF to an EHT-LTF may be called a preamble or aphysical preamble, and may begenerated/transmitted/received/obtained/decoded in a physical layer.

A subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, andEHT-SIG fields of FIG. 18 may be determined as 312.5 kHz, and asubcarrier spacing of the EHT-STF, EHT-LTF, and Data fields may bedetermined as 78.125 kHz. That is, a tone index (or subcarrier index) ofthe L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields may beexpressed in unit of 312.5 kHz, and a tone index (or subcarrier index)of the EHT-STF, EHT-LTF, and Data fields may be expressed in unit of78.125 kHz.

In the PPDU of FIG. 18 , the L-LTE and the L-STF may be the same asthose in the conventional fields.

The L-SIG field of FIG. 18 may include, for example, bit information of24 bits. For example, the 24-bit information may include a rate field of4 bits, a reserved bit of 1 bit, a length field of 12 bits, a parity bitof 1 bit, and a tail bit of 6 bits. For example, the length field of 12bits may include information related to a length or time duration of aPPDU. For example, the length field of 12 bits may be determined basedon a type of the PPDU. For example, when the PPDU is a non-HT, HT, VHTPPDU or an EHT PPDU, a value of the length field may be determined as amultiple of 3. For example, when the PPDU is an HE PPDU, the value ofthe length field may be determined as “a multiple of 3”+1 or “a multipleof 3”+2. In other words, for the non-HT, HT, VHT PPDI or the EHT PPDU,the value of the length field may be determined as a multiple of 3, andfor the HE PPDU, the value of the length field may be determined as “amultiple of 3”+1 or “a multiple of 3”+2.

For example, the transmitting STA may apply BCC encoding based on a ½coding rate to the 24-bit information of the L-SIG field. Thereafter,the transmitting STA may obtain a BCC coding bit of 48 bits. BPSKmodulation may be applied to the 48-bit coding bit, thereby generating48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols topositions except for a pilot subcarrier{subcarrier index −21, −7, +7,+21} and a DC subcarrier{subcarrier index 0}. As a result, the 48 BPSKsymbols may be mapped to subcarrier indices −26 to −22, −20 to −8, −6 to−1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA mayadditionally map a signal of {−1, −1, −1, 1} to a subcarrier index{−28,−27, +27, +28}. The aforementioned signal may be used for channelestimation on a frequency domain corresponding to {−28, −27, +27, +28}.

The transmitting STA may generate an RL-SIG generated in the same manneras the L-SIG. BPSK modulation may be applied to the RL-SIG. Thereceiving STA may know that the RX PPDU is the HE PPDU or the EHT PPDU,based on the presence of the RL-SIG.

A universal SIG (U-SIG) may be inserted after the RL-SIG of FIG. 18 .The U-SIB may be called in various terms such as a first SIG field, afirst SIG, a first type SIG, a control signal, a control signal field, afirst (type) control signal, or the like.

The U-SIG may include information of N bits, and may include informationfor identifying a type of the EHT PPDU. For example, the U-SIG may beconfigured based on two symbols (e.g., two contiguous OFDM symbols).Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4μs. Each symbol of the U-SIG may be used to transmit the 26-bitinformation. For example, each symbol of the U-SIG may betransmitted/received based on 52 data tomes and 4 pilot tones.

Through the U-SIG (or U-SIG field), for example, A-bit information(e.g., 52 un-coded bits) may be transmitted. A first symbol of the U-SIGmay transmit first X-bit information (e.g., 26 un-coded bits) of theA-bit information, and a second symbol of the U-SIB may transmit theremaining Y-bit information (e.g. 26 un-coded bits) of the A-bitinformation. For example, the transmitting STA may obtain 26 un-codedbits included in each U-SIG symbol. The transmitting STA may performconvolutional encoding (i.e., BCC encoding) based on a rate of R=1/2 togenerate 52-coded bits, and may perform interleaving on the 52-codedbits. The transmitting STA may perform BPSK modulation on theinterleaved 52-coded bits to generate 52 BPSK symbols to be allocated toeach U-SIG symbol. One U-SIG symbol may be transmitted based on 65 tones(subcarriers) from a subcarrier index −28 to a subcarrier index +28,except for a DC index 0. The 52 BPSK symbols generated by thetransmitting STA may be transmitted based on the remaining tones(subcarriers) except for pilot tones, i.e., tones −21, −7, +7, +21.

For example, the A-bit information (e.g., 52 un-coded bits) generated bythe U-SIG may include a CRC field (e.g., a field having a length of 4bits) and a tail field (e.g., a field having a length of 6 bits). TheCRC field and the tail field may be transmitted through the secondsymbol of the U-SIG. The CRC field may be generated based on 26 bitsallocated to the first symbol of the U-SIG and the remaining 16 bitsexcept for the CRC/tail fields in the second symbol, and may begenerated based on the conventional CRC calculation algorithm. Inaddition, the tail field may be used to terminate trellis of aconvolutional decoder, and may be set to, for example, “000000”.

The A-bit information (e.g., 52 un-coded bits) transmitted by the U-SIG(or U-SIG field) may be divided into version-independent bits andversion-dependent bits. For example, the version-independent bits mayhave a fixed or variable size. For example, the version-independent bitsmay be allocated only to the first symbol of the U-SIG, or theversion-independent bits may be allocated to both of the first andsecond symbols of the U-SIG. For example, the version-independent bitsand the version-dependent bits may be called in various terms such as afirst control bit, a second control bit, or the like.

For example, the version-independent bits of the U-SIG may include a PHYversion identifier of 3 bits. For example, the PHY version identifier of3 bits may include information related to a PHY version of a TX/RX PPDU.For example, a first value of the PHY version identifier of 3 bits mayindicate that the TX/RX PPDU is an EHT PPDU. In other words, when thetransmitting STA transmits the EHT PPDU, the PHY version identifier of 3bits may be set to a first value. In other words, the receiving STA maydetermine that the RX PPDU is the EHT PPDU, based on the PHY versionidentifier having the first value.

For example, the version-independent bits of the U-SIG may include aUL/DL flag field of 1 bit. A first value of the UL/DL flag field of 1bit relates to UL communication, and a second value of the UL/DL flagfield relates to DL communication.

For example, the version-independent bits of the U-SIG may includeinformation related to a TXOP length and information related to a BSScolor ID.

For example, when the EHT PPDU is divided into various types (e.g.,various types such as an EHT PPDU related to an SU mode, an EHT PPDUrelated to an MU mode, an EHT PPDU related to a TB mode, an EHT PPDUrelated to extended range transmission, or the like), informationrelated to the type of the EHT PPDU may be included in theversion-dependent bits of the U-SIG.

For example, the U-SIG may include: 1) a bandwidth field includinginformation related to a bandwidth; 2) a field including informationrelated to an MCS scheme applied to EHT-SIG; 3) an indication fieldincluding information regarding whether a dual subcarrier modulation(DCM) scheme is applied to EHT-SIG; 4) a field including informationrelated to the number of symbol used for EHT-SIG; 5) a field includinginformation regarding whether the EHT-SIG is generated across a fullband; 6) a field including information related to a type of EHT-LTF/STF;and 7) information related to a field indicating an EHT-LTF length and aCP length.

Preamble puncturing may be applied to the PPDU of FIG. 18 . The preamblepuncturing implies that puncturing is applied to part (e.g., a secondary20 MHz band) of the full band. For example, when an 80 MHz PPDU istransmitted, an STA may apply puncturing to the secondary 20 MHz bandout of the 80 MHz band, and may transmit a PPDU only through a primary20 MHz band and a secondary 40 MHz band.

For example, a pattern of the preamble puncturing may be configured inadvance. For example, when a first puncturing pattern is applied,puncturing may be applied only to the secondary 20 MHz band within the80 MHz band. For example, when a second puncturing pattern is applied,puncturing may be applied to only any one of two secondary 20 MHz bandsincluded in the secondary 40 MHz band within the 80 MHz band. Forexample, when a third puncturing pattern is applied, puncturing may beapplied to only the secondary 20 MHz band included in the primary 80 MHzband within the 160 MHz band (or 80+80 MHz band). For example, when afourth puncturing is applied, puncturing may be applied to at least one20 MHz channel not belonging to a primary 40 MHz band in the presence ofthe primary 40 MHz band included in the 80 MHz band within the 160 MHzband (or 80+80 MHz band).

Information related to the preamble puncturing applied to the PPDU maybe included in U-SIG and/or EHT-SIG. For example, a first field of theU-SIG may include information related to a contiguous bandwidth, andsecond field of the U-SIG may include information related to thepreamble puncturing applied to the PPDU.

For example, the U-SIG and the EHT-SIG may include the informationrelated to the preamble puncturing, based on the following method. Whena bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be configuredindividually in unit of 80 MHz. For example, when the bandwidth of thePPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHzband and a second U-SIG for a second 80 MHz band. In this case, a firstfield of the first U-SIG may include information related to a 160 MHzbandwidth, and a second field of the first U-SIG may include informationrelated to a preamble puncturing (i.e., information related to apreamble puncturing pattern) applied to the first 80 MHz band. Inaddition, a first field of the second U-SIG may include informationrelated to a 160 MHz bandwidth, and a second field of the second U-SIGmay include information related to a preamble puncturing (i.e.,information related to a preamble puncturing pattern) applied to thesecond 80 MHz band. Meanwhile, an EHT-SIG contiguous to the first U-SIGmay include information related to a preamble puncturing applied to thesecond 80 MHz band (i.e., information related to a preamble puncturingpattern), and an EHT-SIG contiguous to the second U-SIG may includeinformation related to a preamble puncturing (i.e., information relatedto a preamble puncturing pattern) applied to the first 80 MHz band.

Additionally or alternatively, the U-SIG and the EHT-SIG may include theinformation related to the preamble puncturing, based on the followingmethod. The U-SIG may include information related to a preamblepuncturing (i.e., information related to a preamble puncturing pattern)for all bands. That is, the EHT-SIG may not include the informationrelated to the preamble puncturing, and only the U-SIG may include theinformation related to the preamble puncturing (i.e., the informationrelated to the preamble puncturing pattern).

The U-SIG may be configured in unit of 20 MHz. For example, when an 80MHz PPDU is configured, the U-SIG may be duplicated. That is, fouridentical U-SIGs may be included in the 80 MHz PPDU. PPDUs exceeding an80 MHz bandwidth may include different U-SIGs.

The U-SIG may be configured in unit of 20 MHz. For example, when an 80MHz PPDU is configured, the U-SIG may be duplicated. That is, fouridentical U-SIGs may be included in the 80 MHz PPDU. PPDUs exceeding an80 MHz bandwidth may include different U-SIGs.

The EHT-SIG of FIG. 18 may include control information for the receivingSTA. The EHT-SIG may be transmitted through at least one symbol, and onesymbol may have a length of 4 μs. Information related to the number ofsymbols used for the EHT-SIG may be included in the U-SIG.

The EHT-SIG may include a technical feature of the HE-SIG-B describedwith reference to FIG. 8 and FIG. 9 . For example, the EHT-SIG mayinclude a common field and a user-specific field as in the example ofFIG. 8 . The common field of the EHT-SIG may be omitted, and the numberof user-specific fields may be determined based on the number of users.

As in the example of FIG. 8 , the common field of the EHT-SIG and theuser-specific field of the EHT-SIG may be individually coded. One userblock field included in the user-specific field may include informationfor two users, but a last user block field included in the user-specificfield may include information for one user. That is, one user blockfield of the EHT-SIG may include up to two user fields. As in theexample of FIG. 9 , each user field may be related to MU-MIMOallocation, or may be related to non-MU-MIMO allocation.

As in the example of FIG. 8 , the common field of the EHT-SIG mayinclude a CRC bit and a tail bit. A length of the CRC bit may bedetermined as 4 bits. A length of the tail bit may be determined as 6bits, and may be set to ‘000000’.

As in the example of FIG. 8 , the common field of the EHT-SIG mayinclude RU allocation information. The RU allocation information mayimply information related to a location of an RU to which a plurality ofusers (i.e., a plurality of receiving STAs) are allocated. The RUallocation information may be configured in unit of 8 bits (or N bits),as in Table 1.

The example of Table 5 to Table 7 is an example of 8-bit (or N-bit)information for various RU allocations. An index shown in each table maybe modified, and some entries in Table 5 to Table 7 may be omitted, andentries (not shown) may be added.

The example of Table 5 to Table 7 relates to information related to alocation of an RU allocated to a 20 MHz band. For example, ‘an index 0’of Table 5 may be used in a situation where nine 26-RUs are individuallyallocated (e.g., in a situation where nine 26-RUs shown in FIG. 5 areindividually allocated).

Meanwhile, a plurality or RUs may be allocated to one STA in the EHTsystem. For example, regarding ‘an index 60’ of Table 6, one 26-RU maybe allocated for one user (i.e., receiving STA) to the leftmost side ofthe 20 MHz band, one 26-RU and one 52-RU may be allocated to the rightside thereof, and five 26-RUs may be individually allocated to the rightside thereof.

TABLE 5 Number Indices #1 #2 #3 #4 #5 #6 #7 #8 #9 of entries 0 26 26 2626 26 26 26 26 26 1 1 26 26 26 26 26 26 26 52 1 2 26 26 26 26 26 52 2626 1 3 26 26 26 26 26 52 52 1 4 26 26 52 26 26 26 26 26 1 5 26 26 52 2626 26 52 1 6 26 26 52 26 52 26 26 1 7 26 26 52 26 52 52 1 8 52 26 26 2626 26 26 26 1 9 52 26 26 26 26 26 52 1 10 52 26 26 26 52 26 26 1 11 5226 26 26 52 52 1 12 52 52 26 26 26 26 26 1 13 52 52 26 26 26 52 1 14 5252 26 52 26 26 1 15 52 52 26 52 52 1 16 26 26 26 26 26 106 1 17 26 26 5226 106 1 18 52 26 26 26 106 1 19 52 52 26 106 1

TABLE 6 Number Indices #1 #2 #3 #4 #5 #6 #7 #8 #9 of entries 20 106 2626 26 26 26 1 21 106 26 26 26 52 1 22 106 26 52 26 26 1 23 106 26 52 521 24 52 52 — 52 52 1 25 242-tone RU empty (with zero users) 1 26 106 26106 1 27-34 242 8 35-42 484 8 43-50 996 8 51-58 2*996 8 59 26 26 26 2626 52 + 26 26 1 60 26 26 + 52 26 26 26 26 26 1 61 26 26 + 52 26 26 26 521 62 26 26 + 52 26 52 26 26 1 63 26 26 52 26 52 + 26 26 1 64 26 26 + 5226 52 + 26 26 1 65 26 26 + 52 26 52 52 1

TABLE 7 66 52 26 26 26 52 + 26 26 1 67 52 52 26 52 + 26 26 1 68 52 52 +26 52 52 1 69 26 26 26 26 26 + 106 1 70 26 26 + 52 26 106 1 71 26 26 5226 + 106 1 72 26 26 + 52 26 + 106 1 73 52 26 26 26 + 106 1 74 52 52 26 +106 1 75 106 + 26 26 26 26 26 1 76 106 + 26 26 26 52 1 77 106 + 26 52 2626 1 78 106 26 52 + 26 26 1 79 106 + 26 52 + 26 26 1 80 106 + 26 52 52 181 106 + 26 106 1 82 106 26 + 106 1

A mode in which the common field of the EHT-SIG is omitted may besupported. The mode in the common field of the EHT-SIG is omitted may becalled a compressed mode. When the compressed mode is used, a pluralityof users (i.e., a plurality of receiving STAs) may decode the PPDU(e.g., the data field of the PPDU), based on non-OFDMA. That is, theplurality of users of the EHT PPDU may decode the PPDU (e.g., the datafield of the PPDU) received through the same frequency band. Meanwhile,when a non-compressed mode is used, the plurality of users of the EHTPPDU may decode the PPDU (e.g., the data field of the PPDU), based onOFDMA. That is, the plurality of users of the EHT PPDU may receive thePPDU (e.g., the data field of the PPDU) through different frequencybands.

The EHT-SIG may be configured based on various MCS schemes. As describedabove, information related to an MCS scheme applied to the EHT-SIG maybe included in U-SIG. The EHT-SIG may be configured based on a DCMscheme. For example, among N data tones (e.g., 52 data tones) allocatedfor the EHT-SIG, a first modulation scheme may be applied to half ofconsecutive tones, and a second modulation scheme may be applied to theremaining half of the consecutive tones. That is, a transmitting STA mayuse the first modulation scheme to modulate specific control informationthrough a first symbol and allocate it to half of the consecutive tones,and may use the second modulation scheme to modulate the same controlinformation by using a second symbol and allocate it to the remaininghalf of the consecutive tones. As described above, information (e.g., a1-bit field) regarding whether the DCM scheme is applied to the EHT-SIGmay be included in the U-SIG. An HE-STF of FIG. 18 may be used forimproving automatic gain control estimation in a multiple input multipleoutput (MIMO) environment or an OFDMA environment. An HE-LTF of FIG. 18may be used for estimating a channel in the MIMO environment or theOFDMA environment.

The EHT-STF of FIG. 18 may be set in various types. For example, a firsttype of STF (e.g., lx STF) may be generated based on a first type STFsequence in which a non-zero coefficient is arranged with an interval of16 subcarriers. An STF signal generated based on the first type STFsequence may have a period of 0.8 μs, and a periodicity signal of 0.8 μsmay be repeated 5 times to become a first type STF having a length of 4μs. For example, a second type of STF (e.g., 2×STF) may be generatedbased on a second type STF sequence in which a non-zero coefficient isarranged with an interval of 8 subcarriers. An STF signal generatedbased on the second type STF sequence may have a period of 1.6 μs, and aperiodicity signal of 1.6 μs may be repeated 5 times to become a secondtype STF having a length of 8 μs. Hereinafter, an example of a sequencefor configuring an EHT-STF (i.e., an EHT-STF sequence) is proposed. Thefollowing sequence may be modified in various ways.

The EHT-STF may be configured based on the following sequence M.

M={−1,−1,−1,1,1,1,−1,1,1,1,−1,1,1,−1,1}  <Equation 1>

The EHT-STF for the 20 MHz PPDU may be configured based on the followingequation. The following example may be a first type (i.e., lx STF)sequence. For example, the first type sequence may be included in not atrigger-based (TB) PPDU but an EHT-PPDU. In the following equation,(a:b:c) may imply a duration defined as b tone intervals (i.e., asubcarrier interval) from atone index (i.e., subcarrier index) ‘a’ toatone index ‘c’. For example, the equation 2 below may represent asequence defined as 16 tone intervals from a tone index −112 to a toneindex 112. Since a subcarrier spacing of 78.125 kHz is applied to theEHT-STR, the 16 tone intervals may imply that an EHT-STF coefficient (orelement) is arranged with an interval of 78.125*16=1250 kHz. Inaddition, * implies multiplication, and sqrt( ) implies a square root.In addition, j implies an imaginary number.

EHT−STF(−112:16:112)={M}*(1+j)/sqrt(2)  <Equation 2>

EHT-STF(0)=0

The EHT-STF for the 40 MHz PPDU may be configured based on the followingequation. The following example may be the first type (i.e., 1×STF)sequence.

EHT-STF(−240:16:240)={M,0,−M}*(1+j)/sqrt(2)  <Equation 3>

The EHT-STF for the 80 MHz PPDU may be configured based on the followingequation. The following example may be the first type (i.e., 1×STF)sequence.

EHT-STF(−496:16:496)={M,1,−M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation 4>

The EHT-STF for the 160 MHz PPDU may be configured based on thefollowing equation. The following example may be the first type (i.e.,1×STF) sequence.

EHT-STF(−1008:16:1008)={M,1,−M,0,−M,1,−M,0,−M,−1,M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation5>

In the EHT-STF for the 80+80 MHz PPDU, a sequence for lower 80 MHz maybe identical to Equation 4. In the EHT-STF for the 80+80 MHz PPDU, asequence for upper 80 MHz may be configured based on the followingequation.

EHT-STF(−496:16:496)={−M,−1,M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation 6>

Equation 7 to Equation 11 below relate to an example of a second type(i.e., 2×STF) sequence.

EHT-STF(−120:8:120)={M,0,−M}*(1+j)/sqrt(2)  <Equation 7>

The EHT-STF for the 40 MHz PPDU may be configured based on the followingequation.

EHT-STF(−248:8:248)={M,−1,−M,0,M,−1,M}*(1+j)/sqrt(2)

EHT-STF(−248)=0

EHT-STF(248)=0  <Equation 8>

The EHT-STF for the 80 MHz PPDU may be configured based on the followingequation.

EHT-STF(−504:8:504)={M,−1,M,−1,−M,−1,M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)  <Equation9>

The EHT-STF for the 160 MHz PPDU may be configured based on thefollowing equation.

EHT-STF(−1016:16:1016)={M,−1,M,−1,−M,−1,M,0,−M,1,M,1,−M,1,−M,0,−M,1,−M,1,M,1,−M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)

EHT-STF(−8)=0,EHT-STF(8)=0,

EHT-STF(−1016)=0,EHT-STF(1016)=0  <Equation 10>

In the EHT-STF for the 80+80 MHz PPDU, a sequence for lower 80 MHz maybe identical to Equation 9. In the EHT-STF for the 80+80 MHz PPDU, asequence for upper 80 MHz may be configured based on the followingequation.

EHT-STF(−504:8:504)={−M,1,−M,1,M,1,−M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)

EHT-STF(−504)=0,

EHT-STF(504)=0  <Equation 11>

The EHT-LTF may have first, second, and third types (i.e., 1×, 2×,4×LTF). For example, the first/second/third type LTF may be generatedbased on an LTF sequence in which a non-zero coefficient is arrangedwith an interval of 4/2/1 subcarriers. The first/second/third type LTFmay have a time length of 3.2/6.4/12.8 μs. In addition, a GI (e.g.,0.8/1/6/3.2 μs) having various lengths may be applied to thefirst/second/third type LTF.

Information related to a type of STF and/or LTF (information related toa GI applied to LTF is also included) may be included in a SIG-A fieldand/or SIG-B field or the like of FIG. 18 .

A PPDU (e.g., EHT-PPDU) of FIG. 18 may be configured based on theexample of FIG. 5 and FIG. 6 .

For example, an EHT PPDU transmitted on a20 MHz band, i.e., a20 MHz EHTPPDU, may be configured based on the RU of FIG. 5 . That is, a locationof an RU of EHT-STF, EHT-LTF, and data fields included in the EHT PPDUmay be determined as shown in FIG. 5 .

An EHT PPDU transmitted on a 40 MHz band, i.e., a 40 MHz EHT PPDU, maybe configured based on the RU of FIG. 6 . That is, a location of an RUof EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may bedetermined as shown in FIG. 6 .

Since the RU location of FIG. 6 corresponds to 40 MHz, a tone-plan for80 MHz may be determined when the pattern of FIG. 6 is repeated twice.That is, an 80 MHz EHT PPDU may be transmitted based on a new tone-planin which not the RU of FIG. 7 but the RU of FIG. 6 is repeated twice.

When the pattern of FIG. 6 is repeated twice, 23 tones (i.e., 11 guardtones+12 guard tones) may be configured in a DC region. That is, atone-plan for an 80 MHz EHT PPDU allocated based on OFDMA may have 23 DCtones. Unlike this, an 80 MHz EHT PPDU allocated based on non-OFDMA(i.e., a non-OFDMA full bandwidth 80 MHz PPDU) may be configured basedon a 996-RU, and may include 5 DC tones, 12 left guard tones, and 11right guard tones.

A tone-plan for 160/240/320 MHz may be configured in such a manner thatthe pattern of FIG. 6 is repeated several times.

The PPDU of FIG. 18 may be determined (or identified) as an EHT PPDUbased on the following method.

A receiving STA may determine a type of an RX PPDU as the EHT PPDU,based on the following aspect. For example, the RX PPDU may bedetermined as the EHT PPDU: 1) when a first symbol after an L-LTF signalof the RX PPDU is a BPSK symbol; 2) when RL-SIG in which the L-SIG ofthe RX PPDU is repeated is detected; and 3) when a result of applying“modulo 3” to a value of a length field of the L-SIG of the RX PPDU isdetected as “0”. When the RX PPDU is determined as the EHT PPDU, thereceiving STA may detect a type of the EHT PPDU (e.g., anSU/MU/Trigger-based/Extended Range type), based on bit informationincluded in a symbol after the RL-SIG of FIG. 18 . In other words, thereceiving STA may determine the RX PPDU as the EHT PPDU, based on: 1) afirst symbol after an L-LTF signal, which is a BPSK symbol; 2) RL-SIGcontiguous to the L-SIG field and identical to L-SIG; 3) L-SIG includinga length field in which a result of applying “modulo 3” is set to “0”;and 4) a 3-bit PHY version identifier of the aforementioned U-SIG (e.g.,a PHY version identifier having a first value).

For example, the receiving STA may determine the type of the RX PPDU asthe EHT PPDU, based on the following aspect. For example, the RX PPDUmay be determined as the HE PPDU: 1) when a first symbol after an L-LTFsignal is a BPSK symbol; 2) when RL-SIG in which the L-SIG is repeatedis detected; and 3) when a result of applying “modulo 3” to a value of alength field of the L-SIG is detected as “1” or “2”.

For example, the receiving STA may determine the type of the RX PPDU asa non-HT, HT, and VHT PPDU, based on the following aspect. For example,the RX PPDU may be determined as the non-HT, HT, and VHT PPDU: 1) when afirst symbol after an L-LTF signal is a BPSK symbol; and 2) when RL-SIGin which L-SIG is repeated is not detected. In addition, even if thereceiving STA detects that the RL-SIG is repeated, when a result ofapplying “modulo 3” to the length value of the L-SIG is detected as “0”,the RX PPDU may be determined as the non-HT, HT, and VHT PPDU.

In the following example, a signal represented as a (TX/RX/UL/DL)signal, a (TX/RX/UL/DL) frame, a (TX/RX/UL/DL) packet, a (TX/RX/UL/DL)data unit, (TX/RX/UL/DL) data, or the like may be a signaltransmitted/received based on the PPDU of FIG. 18 . The PPDU of FIG. 18may be used to transmit/receive frames of various types. For example,the PPDU of FIG. 18 may be used for a control frame. An example of thecontrol frame may include a request to send (RTS), a clear to send(CTS), a power save-poll (PS-poll), BlockACKReq, BlockAck, a null datapacket (NDP) announcement, and a trigger frame. For example, the PPDU ofFIG. 18 may be used for a management frame. An example of the managementframe may include a beacon frame, a (re-)association request frame, a(re-)association response frame, a probe request frame, and a proberesponse frame. For example, the PPDU of FIG. 18 may be used for a dataframe. For example, the PPDU of FIG. 18 may be used to simultaneouslytransmit at least two or more of the control frames, the managementframe, and the data frame.

FIG. 19 illustrates an example of a modified transmission device and/orreceiving device of the present specification.

Each device/STA of the sub-figure (a)/(b) of FIG. 1 may be modified asshown in FIG. 19 . A transceiver 630 of FIG. 19 may be identical to thetransceivers 113 and 123 of FIG. 1 . The transceiver 630 of FIG. 19 mayinclude a receiver and a transmitter.

A processor 610 of FIG. 19 may be identical to the processors 111 and121 of FIG. 1 . Alternatively, the processor 610 of FIG. 19 may beidentical to the processing chips 114 and 124 of FIG. 1 .

A memory 620 of FIG. 19 may be identical to the memories 112 and 122 ofFIG. 1 . Alternatively, the memory 620 of FIG. 19 may be a separateexternal memory different from the memories 112 and 122 of FIG. 1 .

Referring to FIG. 19 , a power management module 611 manages power forthe processor 610 and/or the transceiver 630. A battery 612 suppliespower to the power management module 611. A display 613 outputs a resultprocessed by the processor 610. A keypad 614 receives inputs to be usedby the processor 610. The keypad 614 may be displayed on the display613. A SIM card 615 may be an integrated circuit which is used tosecurely store an international mobile subscriber identity (IMSI) andits related key, which are used to identify and authenticate subscriberson mobile telephony devices such as mobile phones and computers.

Referring to FIG. 19 , a speaker 640 may output a result related to asound processed by the processor 610. A microphone 641 may receive aninput related to a sound to be used by the processor 610.

1. Tone Plan in 802.11Ax WLAN System

In the present specification, a tone plan relates to a rule fordetermining a size of a resource unit (RU) and/or a location of the RU.Hereinafter, a PPDU based on the IEEE 802.11ax standard, that is, a toneplan applied to an HE PPDU, will be described. In other words,hereinafter, the RU size and RU location applied to the HE PPDU aredescribed, and control information related to the RU applied to the HEPPDU is described.

In the present specification, control information related to an RU (orcontrol information related to a tone plan) may include a size andlocation of the RU, information of a user STA allocated to a specificRU, a frequency bandwidth for a PPDU in which the RU is included, and/orcontrol information on a modulation scheme applied to the specific RU.The control information related to the RU may be included in a SIGfield. For example, in the IEEE 802.11ax standard, the controlinformation related to the RU is included in an HE-SIG-B field. That is,in a process of generating a TX PPDU, a transmitting STA may allow thecontrol information on the RU included in the PPDU to be included in theHE-SIG-B field. In addition, a receiving STA may receive an HE-SIG-Bincluded in an RX PPDU and obtain control information included in theHE-SIG-B, so as to determine whether there is an RU allocated to thereceiving STA and decode the allocated RU, based on the HE-SIG-B.

In the IEEE 802.11ax standard, HE-STF, HE-LTF, and data fields may beconfigured in unit of RUs. That is, when a first RU for a firstreceiving STA is configured, STF/LTF/data fields for the first receivingSTA may be transmitted/received through the first RU.

In the IEEE 802.11ax standard, a PPDU (i.e., SU PPDU) for one receivingSTA and a PPDU (i.e., MU PPDU) for a plurality of receiving STAs areseparately defined, and respective tone plans are separately defined.Specific details will be described below.

The RU defined in 11ax may include a plurality of subcarriers. Forexample, when the RU includes N subcarriers, it may be expressed by anN-tone RU or N RUs. A location of a specific RU may be expressed by asubcarrier index. The subcarrier index may be defined in unit of asubcarrier frequency spacing. In the 11ax standard, the subcarrierfrequency spacing is 312.5 kHz or 78.125 kHz, and the subcarrierfrequency spacing for the RU is 78.125 kHz. That is, a subcarrier index+1 for the RU may mean a location which is more increased by 78.125 kHzthan a DC tone, and a subcarrier index −1 for the RU may mean a locationwhich is more decreased by 78.125 kHz than the DC tone. For example,when the location of the specific RU is expressed by [−121:−96], the RUmay be located in a region from a subcarrier index −121 to a subcarrierindex −96. As a result, the RU may include 26 subcarriers.

The N-tone RU may include a pre-set pilot tone.

2. Null Subcarrier and Pilot Subcarrier

A subcarrier and resource allocation in the 802.11ax system will bedescribed.

An OFDM symbol consists of subcarriers, and the number of subcarriersmay function as a bandwidth of a PPDU. In the WLAN 802.11 system, a datasubcarrier used for data transmission, a pilot subcarrier used for phaseinformation and parameter tacking, and an unused subcarrier not used fordata transmission and pilot transmission are defined.

An HE MU PPDU which uses OFDMA transmission may be transmitted by mixinga 26-tone RU, a 52-tone RU, a 106-tone RU, a 242-tone RU, a 484-tone RU,and a 996-tone RU.

Herein, the 26-tone RU consists of 24 data subcarriers and 2 pilotsubcarriers. The 52-tone RU consists of 48 data subcarriers and 4 pilotsubcarriers. The 106-tone RU consists of 102 data subcarriers and 4pilot subcarriers. The 242-tone RU consists of 234 data subcarriers and8 pilot subcarriers. The 484-tone RU consists of 468 data subcarriersand 16 pilot subcarriers. The 996-tone RU consists of 980 datasubcarriers and 16 pilot subcarriers.

1) Null Subcarrier

As shown in FIG. 5 to FIG. 7 , a null subcarrier exists between 26-toneRU, 52-tone RU, and 106-tone RU locations. The null subcarrier islocated near a DC or edge tone to protect against transmit centerfrequency leakage, receiver DC offset, and interference from an adjacentRU. The null subcarrier has zero energy. An index of the null subcarrieris listed as follows.

Channel Width RU Size Null Subcarrier Indices  20 MHz 26, 52 ±69, ±122106 none 242 none 40 MHz 26, 52 ±3, ±56, ±57, ±110, ±137, ±190, ±191,±244 106 ±3, ±110, ±137, ±244 242, 484 none 80 MHz 26, 52 ±17, ±70, ±71,±124, ±151, ±204, ±205, ±258, ±259, ±312, ±313, ±366, ±393, ±446, ±447,±500 106 ±17, ±124, ±151, ±258, ±259, ±366, ±393, ±500 242, 484 none 996none 160 MHz  26, 52, 106 {null subcarrier indices in 80 MHz − 512, nullsubcarrier indices in 80 MHz + 512} 242, 484, 996, none 2 × 996

A null subcarrier location for each 80 MHz frequency segment of the80+80 MHz HE PPDU shall follow the location of the 80 MHz HE PPDU.

2) Pilot Subcarrier

If a pilot subcarrier exists in an HE-LTF field of HE SU PPDU, HE MUPPDU, HE ER SU PPDU, or HE TB PPDU, a location of a pilot sequence in anHE-LTF field and data field may be the same as a location of 4×HE-LTF.In 1×HE-LTF, the location of the pilot sequence in HE-LTF is configuredbased on pilot subcarriers for a data field multiplied 4 times. If thepilot subcarrier exists in 2×HE-LTF, the location of the pilotsubcarrier shall be the same as a location of a pilot in a 4× datasymbol. All pilot subcarriers are located at even-numbered indiceslisted below.

Channel Width RU size Pilot Subcarrier Indices 20 MHz 26, 52 ±10, ±22,±36, ±48, ±62, ±76, ±90, ±102, ±116 106, 242 ±22, ±48, ±90, ±116 40 MHz26, 52 ±10, ±24, ±36, ±50, ±64, ±78, ±90, ±104, ±116, ±130, ±144, ±158,±170, ±184, ±198, ±212, ±224, ±238 106, 242, 484 ±10, ±36, ±78, ±104,±144, ±170, ±212, ±238 80 MHz 26, 52 ±10, ±24, ±38, ±50, ±64, ±78, ±92,±104, ±118, ±130, ±144, ±158, ±172, ±184, ±198, ±212, ±226, ±238, ±252,±266, ±280, ±292, ±306, ±320, ±334, ±346, ±360, ±372, ±386, ±400, ±414,±426, ±440, ±454, ±468, ±480, ±494 106, 242, 484 ±24, ±50, ±92, ±118,±158, ±184, ±226, ±252, ±266, ±292, ±334, ±360, ±400, ±426, ±468, ±494996 ±24, ±92, ±158, ±226, ±266, ±334, ±400, ±468 160 MHz  26, 52, 106,{pilot subcarrier indices in 80 MHz − 512, 242, 484 pilot subcarrierindices in 80 MHz + 512} 996 {for the lower 80 MHz, pilot subcarrierindices in 80 MHz − 512, for the upper 80 MHz, pilot subcarrier indicesin 80 MHz + 512}

At 160 MHz or 80+80 MHz, the location of the pilot subcarrier shall usethe same 80 MHz location for 80 MHz of both sides.

3. HE Transmit Procedure and Phase Rotation

In an 802.11ax wireless local area network (WLAN) system, transmissionprocedures (or transmit procedures) in a physical layer (PHY) include aprocedure for an HE Single User (SU) PPDU, a transmission procedure foran HE extended range (ER) SU PPDU, a transmission procedure for an HEMulti User (MU) PPDU, and a transmission procedure for an HEtrigger-based (TB) PPDU. A FORMAT field of aPHY-TXSTART.request(TXVECTOR) may be the same as HE_SU, HE_MU, HE_ER_SUor HE_TB. The transmission procedures do not describe operations ofoptional features, such as Dual Carrier Modulation (DCM). Among thediverse transmission procedures, FIG. 21 shows only the PHY transmissionprocedure for the HE SU PPDU.

FIG. 20 shows an example of a PHY transmission procedure for HE SU PPDU.

In order to transmit data, the MAC generates a PHY-TXSTART.requestprimitive, which causes a PHY entity to enter a transmit state.Additionally, the PHY is configured to operate in an appropriatefrequency via station management through PLME. Other transmissionparameters, such as HE-MCS, coding type, and transmission power areconfigured through a PHY-SAP by using a PHY-TXSTART.request(TXVECTOR)primitive. After transmitting a PPDU that transfers (or communicates) atrigger frame, a MAC sublayer may issue a PHY-TRIGGER.request togetherwith a TRIGVECTOR parameter, which provides information needed fordemodulating an HE TB PPDU response that is expected of the PHY entity.

The PHY indicates statuses of a primary channel and another channel viaPHY-CCA.indication. The transmission of a PPDU should be started by thePHY after receiving the PHY-TXSTART.request(TXVECTOR) primitive.

After a PHY preamble transmission is started, the PHY entity immediatelyinitiates data scrambling and data encoding. An encoding method for thedata field is based on FEC_CODING, CH_BANDWIDTH, NUM_STS, STBC, MCS, andNUM_USERS parameters of the TXVECTOR.

A SERVICE field and a PSDU are encoded in a transmitter (or transmittingdevice) block diagram, which will be described later on. Data should beexchanged between the MAC and the PHY through a PHY-DATA.request(DATA)primitive that is issued by the MAC and PHY-DATA.confirm primitives thatare issued by the PHY. A PHY padding bit is applied to the PSDU in orderto set a number of bits of the coded PSDU to be an integer multiple of anumber of coded bits per OFDM symbol.

The transmission is swiftly (or quickly) ended by the MAC through aPHY-TXEND.request primitive. The PSDU transmission is ended uponreceiving a PHY-TXEND.request primitive. Each PHY-TXEND.requestprimitive mat notify its reception together with a PHY-TXEND.confirmprimitive from the PHY.

A packet extension and/or a signal extension may exist in a PPDU. APHY-TXEND.confirm primitive is generated at an actual end time of a mostrecent PPDU, an end time of a packet extension, and an end time of asignal extension.

In the PHY, a Guard Interval (GI) that is indicated together with a GIduration in a GI_TYPE parameter of the TXVECTOR is inserted in all dataOFDM symbols as a solution for a delay spread.

If the PPDU transmission is completed, the PHY entity enters a receivestate.

FIG. 21 shows an example of a block diagram of a transmitting device forgenerating each field of an HE PPDU.

In order to generate each field of the HE PPDU, the following blockdiagrams are used.

a) pre-FEC PHY padding

b) Scrambler

c) FEC (BCC or LDPC) encoders

d) post-FEC PHY padding

e) Stream parser

f) Segment parser (for contiguous 160 MHz and non-contiguous 80+80 MHztransmission)

g) BCC interleaver

h) Constellation mapper

i) DCM tone mapper

j) Pilot insertion

k) Replication over multiple 20 MHz (for BW>20 MHz)

l) Multiplication by 1st column of PHE-LTF

m) LDPC tone mapper

n) Segment deparser

o) Space time block code (STBC) encoder for one spatial stream

p) Cyclic shift diversity (CSD) per STS insertion

q) Spatial mapper

r) Frequency mapping

s) Inverse discrete Fourier transform (IDFT)

f) Cyclic shift diversity (CSD) per chain insertion

u) Guard interval (GI) insertion

v) Windowing

FIG. 21 shows a block diagram of a transmitting device (or transmitterblock diagram) that is used for generating a data field of an HE SingleUser (SU) PPDU having LDPC encoding applied thereto and beingtransmitted at a 160 MHz. If the transmitter block diagram is used forgenerating a data field of an HE SU PPDU that is transmitted in an 80+80MHz band, a segment deparser is not used as shown in FIG. 21 . That is,the block diagram of the transmitter (or transmitting device) is usedper 80 MHz band in a situation where the band is divided into an 80 MHzband and another 80 MHz band by using a segment parser.

Referring to FIG. 21 , an LDPC encoder may encode a data field (or databitstream). The data bitstream input to the LDPC encoder may bescrambled by a scrambler.

A stream parser divides the data bitstream encoded by the LDPC encoderinto a plurality of spatial streams. At this time, an encoded databitstream divided into each spatial stream may be referred to as aspatial block. The number of spatial blocks may be determined by thenumber of spatial streams used to transmit a PPDU and may be set to beequal to the number of spatial streams.

The stream parser divides each spatial block into at least one or moredata segments. As shown in FIG. 21 when the data field is transmitted ina 160 MHz band, the 160 MHz band is divided into two 80 MHz bands, andthe data field is divided into a first data segment and a second datasegment for the respective 80 MHz bands. Afterward, the first and seconddata segments may be constellation mapped to the respective 80 MHz bandsand may be LDPC mapped.

In HE MU transmission, except that cyclic shift diversity (CSD) isperformed based on the information on a space-time stream start indexfor the corresponding user, a PPDU encoding processor is runindependently in a Resource Unit (RU) for each user even for an input toa space mapping block. All the user data of the RU are mapped by beingcoupled to a transmission chain of the space mapping block.

In the 802.11ax, phase rotation may be applied to the field from thelegacy preamble to the field just before the HE-STF, and a phaserotation value may be defined in units of 20 MHz bands. In other words,phase rotation may be applied to L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A,and HE-SIG-B among fields of the HE PPDU defined in the 802.11ax.

The L-STF field of the HE PPDU may be constructed as follows.

-   -   a) Determine the channel bandwidth from the TXVECTOR parameter        CH_BANDWIDTH.    -   b) Sequence generation: Generate the L-STF sequence over the        channel bandwidth as described in 27.3.11.3 (L-STF). Apply a 3        dB power boot if transmitting an HE ER SU PPDU as described in        27.3.11.3 (L-STF).    -   c) Phase rotation: Apply appropriate phase rotation for each 20        MHz subchannel as described in 27.3.11) (Mathematical        description of signals) and 21.3.7.5 (Definition of tone        rotation).    -   d) CSD per STS: If the TXVECTOR parameter BEAM_CHANGE is 0,        apply CSD per STS for each space-time stream and frequency        segment as described in 27.3.11.2.2 (Cyclic shift for HE        modulated fields).    -   c) Spatial mapping: If the TXVECTOR parameter BEAM_CHANGE is 0,        apply the 0.1 matrix and the Q matrix as described in 27.3.11.3        (L-STF).    -   f) IDFT: Compute the inverse discrete Fourier transform.    -   g) CSD per chain: If the TXVECTOR parameter BEAM CHANGE is 1 or        not present apply CSD per chain for each transmit chain and        frequency segment as described in 27.3.11.2.1 (Cyclic shift for        pre-HE modulated fields).    -   h) Insert GI and apply windowing: Prepend a GI (T_(GI,Pre-HE))        and apply windowing as described in 27.3.10 (Mathematical        description of signals).    -   i) Analog and RP. Upconvert the resulting complex baseband        waveform associated with each transmit chain to an RF signal        according to the center frequency of the desired channel and        transmit. Refer to 27.3.10 (Mathematical description of signals)        and 27.3.11 (HE preamble) for details.

The L-LTF field of the HE PPDU may be constructed as follows.

-   -   a) Determine the channel bandwidth from the TXVECTOR parameter        CH_BANDWIDTH.    -   b) Sequence generation: Generate the L-LTF sequence over the        channel bandwidth as described in 27.3.11.4 (L-LTF) Apply a 3 dB        power boost if transmitting an HE ER SU PPDU as described in        27.3.11.4 (L-LTF).    -   c) Phase rotation: Apply appropriate phase rotation for each 20        MHz subchannel as described in 27.3.10 (Mathematical description        of signals) and 21.3.7.5 (Definition of tone rotation).    -   d) CSD per STS: If the TXVECTOR parameter BEAM_CHANGE is 0,        apply CSI) per STS for each space-time stream and frequency        segment as described in 27.3.11.2.2 (Cyclic shift for HE        modulated fields) before spatial mapping.    -   c) Spatial mapping: If the TXVECTOR parameter BEAM_CHANGE is 0,        apply the A matrix and the Q matrix as described in 27.3.11.4        (L-LTF).    -   f) IDFT: Compute the inverse discrete Fourier transform.    -   g) CSD per chain: If the TXVECTOR parameter BEAM_CHANGE is 1 or        not present, apply CSI) per chain for each transmit chain and        frequency segment as described in 27.3.11.2.1 (Cyclic shift for        pre-HE modulated fields).    -   h) Insert GI and apply windowing: Prepend a GI (T_(GI,L-LTE))        and apply windowing as described in 27.3.10 (Mathematical        description of signals).    -   i) Analog and RF: Upconvert the resulting complex baseband        waveform associated with each transmit chain to an RF signal        according to the cannier frequency of the desired channel and        transmit. Refer to 27.3.10 (Mathematical description of signals)        and 27.3.11 (HE preamble) for details.

The L-SIG field of the HE PPDU may be constructed as follows.

-   -   a) Set the RATE subfield in the SIGNAL field to 6 Mb/s. Set the        LENGTH, Parity, and Tail fields in time SIGNAL field as        described in 27.3.11.5 (L-SIG).    -   b) BCC encoder: Encode the SIGNAL field by a convolutional        encoder at the rate of R=1/2 as described in 27.3.12.5.1 (BCC        coding and puncturing).    -   c) BCC inlerleaver: Interleave as described in 17.3.5.7 (BCC        interleavers).    -   d) Constellation Mapper: BPSK modulate as described in 27.3.12.9        (Constellation mapping).    -   e) Pilot insertion Insert pilots as described in 27.3.11.5        (L-SIG).    -   f) Extra subcarrier insertion: Four extra subcarriers are        inserted at k∈{−28, −27, 27, 28} for channel estimation purpose        and the values on these four extra subcarriers are {−1, −1, −1,        1}, respectively.

Apply a 3 dB power boost to the four extra subcarriers i transmitting anHE ER SU PPDU as described in 27.3.11.5 (L-SIG).

-   -   g) Duplication and phase rotation: Duplicate the L-SIG field        over each occupied 20 MHz subchannel of the channel bandwidth.        Apply appropriate phase rotation for each occupied 20 MHz        subchannel as described in 27.3.10 (Mathematical description of        signals) and 21.3.7.5 (Definition of tone rotation).    -   h) CSD per STS: If the TXVECTOR parameter BEAM_CHANGE is 0,        apply CSD per STS for each space-time stream and frequency        segment as described in 27.3.11.2.2 (Cyclic shift for HE        modulated fields) before spatial mapping.    -   i) Spatial mapping: If the TXVECTOR parameter BEAM_CHANGE is 0,        apply the A matrix and Q matrix as described in 27.3.11.5        (L-SIG).    -   j) IDFT: Compute the inverse discrete Fourier transform.    -   k) CSD per chain: If the TXVECTOR parameter BEAM, CHANGE is 1 or        not present, apply CSD per chain for each transmit chain and        frequency segment as described in 27.3.11.2.1 (Cyclic shift for        pre-HE modulated fields).    -   l) Insert GI and apply windowing: Prepend a GI (T_(GI,Pre-HE))        and apply windowing as described in 27.3.10 (Mathematical        description of signals).    -   m) Analog and RF: Upconvert the resulting complex baseband        waveform associated with each transmit chain. Refer to 27.3.10        (Mathematical description of signals) and 27.3.11 (HE preamble)        for details.

The RL-SIG field of the HE PPDU may be constructed as follows.

-   -   a) Set the RATE subfield in the repeat SIGNAL field to 6 Mb/s.        Set the LENGTH Parity, and Tail fields in the repeat SIGNAL        field as described in 27.3.11.6 (RL-SIG).    -   b) BCC encoder: Encode the repeat SIGNAL field by a        convolutional encoder at the mite of R=1/2 as described in        27.3.12.5.1 (BCC coding and puncturing).    -   c) BCC interleaver: Interleave as described in 17.3.5.7 (BCC        interleavers).    -   d) Constellation Mapper: BPSK modulate as described in 27.3.12.9        (Constellation mapping).    -   e) Pilot insertion: Insert pilots as described in 27.3.11.6        (RL-SIG).    -   f) Extra subcarrier insertion: Four extra subcarriers are        inserted at k∈{−28, −27, 27, 28} for channel estimation purpose        and the values on these four extra subcarriers are {−1, −1, −1,        1}, respectively. Apply a 3 dB power boost to the four extra        subcarriers if transmitting an HE ER SU PPDU as described in        27.3.11.6 (RL-SIG).    -   g) Duplication and phase rotation Duplicate the RL-SIG field        over each occupied 20 MHz subchannel of the channel bandwidth.        Apply appropriate phase rotation for each occupied 20 MHz        subchannel as described in 27.3.10 (Mathematical description of        signals) and 21.3.7.5 (Definition of tone rotaion).    -   b) CSD per STS: If the TXVECTOR parameter BEAM_CHANGE is 0,        apply CSD per STS for each space-time stream and frequency        segment as described in 27.3.11.2.2 (Cyclic shift for HE        modulated fields) before spatial mapping.    -   i) Spatial mapping: If the TXVECTOR parameter BEAM_CHANGE is 0,        apply the A matrix and the Q matrix as described in 27.3.11.6        (RL-SIG).    -   j) IDFT: Compute the inverse discrete Fourier transform.    -   k) CSD per chain: If the TXVECTOR parameter BEAM_CHANGE is 1 or        not present, apply CSD per chain for each transmit chain and        frequency segment as described in 27.3.11.2.1 (Cyclic shift for        pre-HE modulated fields)    -   1) Insert GI and apply windowing: Prepend a GI (T_(GI,Pre,HS))        and apply windowing as described in 27.3.10 (Mathematical        description of signals).    -   m) Analog and RF: Upconvert the resulting complex baseband        waveform associated with each transmit chain. Refer to 27.3.111        (Mathematical description of signals) and 27.1.11 (HE preamble)        for details.

4. Embodiment Applicable to the Present Disclosure

In the wireless LAN 802.11 system, to increase peak throughput, it isconsidered to use a wider band than the existing 11ax or to transmit anincreased stream by using more antennas. In addition, the presentspecification also considers a method of aggregating multiple links oraggregating multiple RUs and allocating them to one STA fortransmission.

This specification considers a method of allocating and transmittingmultiple resource units (RUs) to one STA, and in this case, proposes amethod of aggregating RUs in various bandwidths. In particular, it isproposed by focusing on a method of aggregating RUs with a small size.

In the existing 802.11ax, OFDMA transmission was introduced, and amethod of allocating and transmitting only one RU to one STA wasconsidered. In this case, some RUs cannot be used for transmission, sospectrum is wasted, and since fixed RUs are used, there is adisadvantage in terms of efficiency. Accordingly, 11be is considering amethod of allocating and transmitting multiple RUs to one STA forefficiency improvement and efficient spectrum use. In thisspecification, several principles and various combinations for RUaggregation are proposed in this regard.

The RUs of various sizes proposed in 802.11ax are as follows.

26/52/106/242/484/996/2×996 RU

In the present specification, it is assumed that an RU having less than242 tones is a small-RU and an RU having more than 242 tones is alarge-RU. In addition, in terms of efficiency, the combination ofsmall-RU and large-RU does not have a large gain, so only a combinationbetween small-RUs and a combination between large-RUs can be consideredduring RU aggregation. In this specification, a combination of small-RUis proposed.

4.1. Rule

A. In order to prevent scheduling and hardware complexity fromincreasing due to various combinations, consider that only two RUs areaggregated. However, there are exceptions to this, which areadditionally suggested in 4.2. Combination.

B. In RU aggregation, only combinations with adjacent RUs are consideredbecause the combination of non-adjacent RUs has relatively little gainin terms of frequency diversity as well as complexity increase. It isalready possible to obtain sufficient diversity gain by means of aninterleaver, a tone mapper, or Multi-Input Multi-Output (MIMO).

C. This is not taken into account because a combination of RUs of thesame size can be extended to an RU of the next size. However, there areexceptions to this, which are additionally suggested in 4.2.Combination.

D. When combining RUs, only RUs within 20 MHz are combined because thereis a gain in decoding of the receiver considering the existing 11axSIG-B design as well as increase in complexity. However, exceptions tothis may be considered, and this is additionally suggested in 4.2.Combination.

4.2. Combination

FIG. 22 shows an example of an 80 MHz tone plan in which 20 MHzpuncturing is performed.

Various RU aggregation combinations will be described with reference toFIG. 22 . The description of FIG. 22 is based on 80 MHz, but in160/80+80/240/160+80/320/160+160 MHz, the 80 MHz tone plan of FIG. 22 isrepeatedly used, so it is extended as it is for each 80 MHz unit can do.

Referring to FIG. 22 , the 20 MHz of the lowest frequency is the primary20 MHz (P20), the 20 MHz of the next low frequency is the secondary 20MHz (S20), and the 40 MHz of the highest frequency is the secondary 40MHz (S40). FIG. 22 shows a situation in which S20 is punctured. In thiscase, RUs indicated by 242-1, 106-2, 52-4, 26-9, and 26-19 may not usedto reduce interference. Here, 242-1 means an RU indicated by number 1among 242-tone RUs. Based on the tone plan of FIG. 22 , an RUcombination is proposed as follows.

When the 4.1. Rule is considered, the following various RU combinationscan be considered. Considering the situation in which S20 is notpuncturing, the following is the RU combination in P20.

(26-2, 52-2), (52-1, 26-3), (52-2, 26-5), (106-1, 26-5), (26-5, 52-3),(26-5, 106-2), (26-7, 52-4), (52-3, 26-8)

The following is the RU combination in S20.

(26-11, 52-6), (52-5, 26-12), (52-6, 26-14), (106-3, 26-14), (26-14,52-7), (26-14, 106-4), (26-16, 52-8), (52-7, 26-17)

The following is the RU combination in lower 20 MHz of S40.

(26-21, 52-10), (52-9, 26-22), (52-10, 26-24), (106-5, 26-24), (26-24,52-11), (26-24, 106-6), (26-26, 52-12), (52-11, 26-27)

The following is the RU combination in higher 20 MHz of S40.

(26-30, 52-14), (52-13, 26-31), (52-14, 26-33), (106-7, 26-33), (26-33,52-15), (26-33, 106-8), (26-35, 52-16), (52-15, 26-36)

Exceptions in 4.1. Rule A above are as follows. As shown in FIG. 22 ,when S20 is preamble punctured, only some RUs may be used in P20. Inthis case, if only one RU is allocated to P20, the following RUcombination may be additionally considered.

(106-1, 26-5, 52-3, 26-8)

If it is assumed that P20 is the location of S20 in the figure above andS20 is the location of P20 in the figure above, if S20 is preamblepunctured in this situation, P20 may additionally consider the followingRU combination.

(26-11, 52-6, 26-14, 106-4)

If 20 MHz of the highest frequency is preamble punctured, the followingRU combination may be additionally considered at 20 MHz of the secondhigh frequency.

(106-5, 26-24, 52-11, 26-27)

If 20 MHz of the second high frequency is preamble punctured, thefollowing RU combination may be additionally considered at 20 MHz of thehighest frequency.

(26-30, 52-14,26-33, 106-8)

Exceptions in 4.1. Rule C above are as follows. A combination between26-tone RUs of the same size is considered, which is limited to the casewhere two combinations are not extended to a 52-tone RU. The RUcombination according to this is as follows.

(26-2, 26-3), (26-4, 26-5), (26-5, 26-6), (26-7, 26-8)

(26-11, 26-12), (26-13, 26-14), (26-14, 26-15), (26-16, 26-17)

(26-21, 26-22), (26-23, 26-24), (26-24, 26-25), (26-26, 26-27)

(26-30, 26-31), (26-32, 26-33), (26-33, 26-34), (26-35, 26-36)

Exceptions in 4.1. Rule D above are as follows. A combination of RUs atthe boundary between P20 and S20 may be considered, and thecorresponding RU combination is as follows.

(26-9, 26-10), (26-9, 52-5), (26-9, 106-3), (52-4, 26-10), (52-4, 52-5),(52-4, 106-3), (106-2, 26-10), (106-2, 52-5), (106-2, 106-3)

A combination of RUs on the boundary between 20 MHz of the second highfrequency and 20 MHz of the highest frequency can be considered, and theRU combination is as follows.

(26-28, 26-29), (26-28, 52-13), (26-28, 106-7), (52-12, 26-29), (52-12,52-13), (52-12, 106-7), (106-6, 26-29), (106-6, 52-13), (106-6, 106-7)

Considering the combination between S20 and the RU at the 20 MHzboundary of the second high frequency, the corresponding RU combinationis as follows.

(26-18, 26-19), (52-8, 26-19), (106-4, 26-19), (26-19, 26-20), (26-19,52-9), (26-19, 106-5)

4.3. Signaling Method

FIG. 23 shows an example of an EHT PPDU format.

FIG. 24 shows an example of a U-SIG format.

The above-described indicator regarding RU aggregation may betransmitted within the EHT-SIG of the EHT PPDU of FIG. 23 or the U-SIGof FIG. 24 .

The Version independent field of FIG. 24 may include a 3-bit versionidentifier indicating a Wi-Fi version after 802.11be and 802.11be, a1-bit DL/UL field, a BSS color, and a TXOP duration, and the like, theversion dependent field of FIG. 24 may include information such as PPDUtype and Bandwidth.

In U-SIG, two symbols are jointly encoded and each 20 MHz consists of 52data tones and 4 pilot tones. Also, U-SIG is modulated in the same wayas HE-SIG-A. That is, the U-SIG is modulated with a BPSK 1/2 code rate.

The EHT-SIG can be divided into a common field and a user specificfield, can be encoded with a variable MCS, and can indicate informationabout an accurate puncturing pattern and RU aggregation used fortransmission in the common field. Additionally, in order to whenpreamble puncturing is applied, it indicates whether to apply a shiftedtone plan in an adjacent 20 MHz channel or change to a 20 MHz tone plan,or whether to use the tone plan as it is but puncture some tones ortransmit some tones with low power, one bit of information may betransmitted in the version dependent field of the U-SIG or the commonfield of the EHT-SIG.

FIG. 25 is a procedure flowchart illustrating an operation of atransmission apparatus according to the present embodiment.

The example of FIG. 25 may be performed by a transmitting device (APand/or non-AP STA). For example, the example of FIG. 25 may be performedby an AP transmitting an EHT SU PPDU, an EHT ER SU PPDU, or an EHT MUPPDU. The example of FIG. 25 may be performed by a non-AP that transmitsan EHT SU PPDU, an EHT ER SU PPDU, and an EHT MU PPDU.

Some of each step (or detailed sub-step to be described later) of theexample of FIG. 25 may be omitted or changed.

In step S2510, the transmitting device (i.e., transmitting STA)configures Bandwidth (BW) and RU allocation, and allocates multiple RUsto a specific user or STA by the Multiple RU aggregation combination ofparagraph 4.2 of the above specification. Also, the transmitting devicemay perform a channel access operation.

In step S2520, the transmitting STA may configure a PPDU. For example,the PPDU may be an EHT SU PPDU, an EHT ER SU PPDU, or an EHT MU PPDU.The PPDU may include an EHT-SIG as shown in FIG. 18 .

The transmitting STA may perform step S2520 based on the BW, RUallocation, and multiple RU aggregation determined in step S2510.

That is, as described above, specific (RU allocation) n-bit (e.g.,8-bit) information may be included in the common field of the EHT-SIG,and information on multiple RU aggregation may be included in the userspecific field.

In step S2530, the transmitting device may transmit the PPDU configuredin step S2520 to the receiving device based on step S2530.

While performing step S2530, the transmitting device may perform atleast one of CSD, spatial mapping, IDFT/IFFT operation, GI insertion,and the like.

A signal/field/sequence constructed according to this specification maybe transmitted in the form of FIG. 18 .

For example, the above-described EHT-SIG may be transmitted based onseveral OFDM symbols. For example, one OFDM symbol may include 26-bitinformation. The 26-bit information may include the above-described4-bit BW information. Any m-bit information may be used instead of26-bit information.

For 26-bit information, BCC encoding with 1/2 inefficiency may beapplied. Interbiring by an interleaver may be applied to the BCC codedbits (ie, 52 bits). Constellation mapping by a constellation mapper maybe performed on the interleaved 52 bits. Specifically, the BPSK modulemay be applied to generate 52 BPSK symbols. The 52 BSPK symbols may bematched to the remaining frequency domains (−28 to +28) except for DCtones and pilot tones (−21, −7, +7, +21) tones. Thereafter, it may betransmitted to the receiving STA through phase rotation, CSD, spatialmapping, IDFT/IFFT operation, and the like.

The above-described PPDU may be transmitted based on the apparatus ofFIG. 1 .

The example of FIG. 1 relates to an example of a transmitting apparatus(AP and/or non-AP STA).

As shown in FIG. 1 , the transmitting apparatus (or transmitter) mayinclude a memory 112, a processor 111, and a transceiver 113.

The memory 112 may store information on a plurality of Tone-Plan/RU thatare described in the present specification.

The processor 111 may generate various RUs based on information storedin the memory 112 and configure a PPDU. An example of the PPDU generatedby the processor 111 may be as shown in FIG. 18 .

The processor 111 may perform all/part of the operations illustrated inFIG. 25 .

The illustrated transceiver 113 includes an antenna and may performanalog signal processing. Specifically, the processor 111 may controlthe transceiver 113 to transmit the PPDU generated by the processor 111.

Alternatively, the processor 111 may generate a transmission PPDU andstore information about the transmission PPDU in the memory 112.

FIG. 26 is a procedure flowchart illustrating an operation of areception apparatus according to the present embodiment.

An example of FIG. 26 may be performed in the reception apparatus (APand/or non-AP STA).

The example of FIG. 26 may be performed by a reception apparatus (APand/or non-AP STA). For example, the example of FIG. 26 may be performedby a non-AP receiving an EHT SU PPDU, an EHT ER SU PPDU, or an EHT MUPPDU. The example of FIG. 26 may be performed by an AP that transmits anEHT SU PPDU, an EHT ER SU PPDU.

Some of each step (or detailed sub-step to be described later) of theexample of FIG. 26 may be omitted.

In step S2610, the receiving device (receiving STA) may receive all orpart of the PPDU through step S2610. The received signal may be in theform of FIG. 18 .

The sub-step of step S2610 may be determined based on step S2530 of FIG.25 . That is, in step S2610, an operation for restoring the results ofthe CSD, spatial mapping, IDFT/IFFT operation, and GI insert operationapplied in step S2530 may be performed.

In step S2620, the receiving STA may obtain information on the BW, RUallocation, and multiple RU aggregation of the EHT PPDU by decodinginformation included in the U-SIG or EHT-SIG.

Through this, the receiving STA can complete decoding of otherfields/symbols of the received PPDU.

As a result, the receiving STA may decode the data field included in thePPDU through step S2620. Thereafter, the receiving STA may perform aprocessing operation of transferring data decoded from the data field toa higher layer (eg, MAC layer). In addition, when generation of a signalis instructed from the upper layer to the PHY layer in response to datatransferred to the upper layer, a subsequent operation may be performed.

The above-described PPDU may be transmitted based on the apparatus ofFIG. 1 .

As shown in FIG. 1 , the reception apparatus may include a memory 112, aprocessor 111, and a transceiver 113.

The transceiver 123 may receive the PPDU based on the control of theprocessor 121. For example, the transceiver 123 may include a pluralityof sub-units (not shown). For example, the transceiver 123 may includeat least one receiving antenna and a filter for the correspondingreceiving antenna.

The PPDU received through the transceiver 123 may be stored in thememory 122. The processor 121 may process decoding of the received PPDUthrough the memory 122. The processor 121 may obtain control information(e.g., EHT-SIG) regarding the Tone-Plan/RU included in the PPDU, andstore the obtained control information in the memory 122.

The processor 121 may perform decoding on the received PPDU.Specifically, an operation for restoring the result of CSD, SpatialMapping, IDFT/IFFT operation, and GI insert applied to the PPDU may beperformed. CSD, Spatial Mapping, IDFT/IFFT operation, and operation ofrestoring the result of GI insert may be performed through a pluralityof processing units (not shown) individually implemented in theprocessor 121.

In addition, the processor 121 may decode the data field of the PPDUreceived through the transceiver 123.

In addition, the processor 121 may process the decoded data. Forexample, the processor 121 may perform a processing operation oftransferring information about the decoded data field to an upper layer(e.g., a MAC layer). In addition, when generation of a signal isinstructed from the upper layer to the PHY layer in response to datatransferred to the upper layer, a subsequent operation may be performed.

Hereinafter, the aforementioned embodiment is described with referenceto FIGS. 1 to 26 .

FIG. 27 is a flowchart illustrating a procedure in which a transmittingSTA transmits a PPDU according to the present embodiment.

An example of FIG. 27 may be performed in a network environment in whicha next-generation wireless LAN system (e.g., IEEE 802.11be or EHTwireless LAN system) is supported. The next-generation wireless LANsystem is a wireless LAN system improved from the 802.11 ax system, andmay satisfy backward compatibility with the 802.11ax system.

The example of FIG. 27 is performed by a transmitting STA, and thetransmitting STA may correspond to an access point (AP). The receivingSTA of FIG. 27 may correspond to an STA supporting an Extremely HighThroughput (EHT) WLAN system.

This embodiment proposes a method and apparatus for transmitting andreceiving PPDU based on multiple RUs configured by a combination betweensmall-RUs. In this case, small-RU means a resource unit having less than242 tones. In particular, this embodiment proposes multiple RUs in which26RU and 52RU are aggregated in each 20 MHz subchannel of a band fortransmitting the PPDU.

In step S2710, the transmitting station (STA) generates a PhysicalProtocol Data Unit (PPDU).

In step S2720, the transmitting STA transmits the PPDU to the receivingSTA through a first band.

The PPDU includes a control field and a data field.

When the first band is an 80 MHz band including first to fourth 20 MHzsubchannels, the first 20 MHz subchannel includes first multipleresource units (RUs) in which a first 26RU and a first 52RU areaggregated. The first 26RU is an RU located in the middle of the first20 MHz subchannel. The first 52RU is an RU having a lower frequency thanthe first 26RU and is adjacent to the first 26RU.

In this embodiment, the first band may be divided into four 20 MHzsubchannels. For example, the first to fourth 20 MHz subchannels may bearranged in order from a subchannel having a low frequency to asubchannel having a high frequency. For example, the first 20 MHzsubchannel is a 20 MHz subchannel having the lowest frequency (or aprimary 20 MHz channel), the second 20 MHz subchannel is a 20 MHzsubchannel having the second lowest frequency (or a secondary 20 MHzchannel), the third 20 MHz subchannel is a 20 MHz subchannel having thethird lowest frequency (or a lower 20 MHz channel among a secondary 40MHz channel), and the fourth 20 MHz subchannel is a 20 MHz subchannelhaving the highest frequency (or a higher 20 MHz channel among the 40MHz channel). In addition, puncturing in units of 20 MHz may beperformed in the first band.

The second 20 MHz subchannel may include second multiple RUs in which asecond 26RU and a second 52RU are aggregated. The second 26RU may be anRU located in the middle of the second 20 MHz subchannel. The second52RU may be an RU having a lower frequency than the second 26RU andadjacent to the second 26RU.

The third 20 MHz subchannel may include third multiple RUs in which athird 26RU and a third 52RU are aggregated. The third 26RU may be an RUlocated in the middle of the third 20 MHz subchannel. The third 52RU maybe an RU having a lower frequency than the third 26RU and adjacent tothe third 26RU.

The fourth 20 MHz subchannel may include fourth multiple RUs in which afourth 26RU and a fourth 52RU are aggregated. The fourth 26RU may be anRU located in the middle of the fourth 20 MHz subchannel. The fourth52RU may be an RU having a lower frequency than the fourth 26RU andadjacent to the fourth 26RU.

The control field may include allocation information on the first tofourth multiple RUs. The receiving STA may decode the control field andidentify the RU allocated to itself among the first to fourth multipleRUs. That is, when multiple RUs are allocated to the receiving STA basedon the control field, the receiving STA may receive a data field throughthe allocated multiple RUs. For example, when all of the first to fourthmulti-RUs are allocated to the receiving STA based on the control field,the data field may be received through the first to fourth multiple RUs.

In this case, the first to fourth 26RUs may be RUs consisting of 26tones, and the first to fourth 52RUs may be RUs consisting of 52 tones.

This embodiment proposes an aggregation method between RUs allocated ineach 20 MHz subchannel of an 80 MHz band. However, it is not limited tothe transmission of the 80 MHz band, and the present embodiment isequally applicable to the transmission of the 20 MHz band, the 40 MHzband, the 160/80+80 MHz band, and the 320/160+160 MHz band. The toneplan of the 20 MHz band and 40 MHz band defined in the EHT wireless LANsystem is the same as the tone plan defined in 802.11ax. Since the toneplan of the 160/80+80 MHz band and the 320/160+160 MHz band repeatedlyuses the 80 MHz band tone plan, the allocation of multiple RUs in the160/80+80 MHz band and the 320/160+160 MHz band may be extended andapplied for every 80 MHz channel. Specific examples are as follows.

When the first band is a 160/80+80 MHz band including first to second 80MHz subchannels, each of the first to second 80 MHz subchannels mayinclude fifth to eighth 20 MHz subchannels. The fifth, sixth, seventh oreighth 20 MHz subchannel may include fifth multiple RUs in which a fifth26RU and a fifth 52RU are aggregated. That is, the present embodimentmay be performed in units of each 80 MHz subchannel for the 160/80+80MHz band, and specifically, in each of the 80 MHz subchannels, multipleRUs in which 52RU and 26 RU are aggregated for each 20 MHz subchannelmay be allocated.

Similarly, the fifth 26RU may be a RU located in the middle of thefifth, sixth, seventh or eighth 20 MHz subchannel, the fifth 52RU may bean RU having a lower frequency than the fifth 26RU and adjacent to thefifth 26RU. In this case, the fifth 26RU may be an RU consisting of 26tones, and the fifth 52RU may be an RU consisting of 52 tones.

The control field may include allocation information on the fifthmultiple RUs. The receiving STA may decode the control field andidentify the RU allocated to itself (fifth multiple RUs). That is, whenmultiple RUs are allocated to the receiving STA based on the controlfield, the receiving STA may receive a data field through the allocatedmultiple RUs. For example, when the fifth multiple RUs are allocated tothe receiving STA based on the control field, the data field may bereceived through the fifth multiple RUs.

When the first band is a 320/160+160 MHz band including first to fourth80 MHz subchannels, each of the first to fourth 80 MHz subchannels mayinclude ninth to twelfth 20 MHz subchannels. The ninth, tenth, eleventhor twelfth 20 MHz subchannel may include sixth multiple RUs in which asixth 26RU and a sixth 52RU are aggregated. That is, the presentembodiment may be performed in units of each 80 MHz subchannel for the320/160+160 MHz band, and specifically, in each of the 80 MHzsubchannels, multiple RUs in which 52RU and 26 RU are aggregated foreach 20 MHz subchannel may be allocated.

Similarly, the sixth 26RU may be a RU located in the middle of theninth, tenth, eleventh or twelfth 20 MHz subchannel, the sixth 52RU maybe an RU having a lower frequency than the sixth 26RU and adjacent tothe sixth 26RU. In this case, the sixth 26RU is an RU consisting of 26tones. The sixth 52RU is an RU consisting of 52 tones.

The control field may include allocation information on the sixthmultiple RUs. The receiving STA may decode the control field andidentify the RU allocated to itself (sixth multiple RUs). That is, whenmultiple RUs are allocated to the receiving STA based on the controlfield, the receiving STA may receive a data field through the allocatedmultiple RUs. For example, when the sixth multiple RUs are allocated tothe receiving STA based on the control field, the data field may bereceived through the sixth multiple RUs.

The control field includes a first control field supporting a legacywireless LAN system and a second control field supporting an 802.11bewireless LAN system. The second control field may include auniversal-signal (U-SIG) or an extremely high throughput-signal(EHT-SIG). The second control field may include allocation informationon an RU to which the data field is to be transmitted. This embodimentdescribes a case where the RU to which the data field is transmitted isa multi-RU in which a plurality of RUs are aggregated with each other.The RU means a resource unit in which the data field is transmitted.

In addition, when the first band is an 80 MHz band, the tone plan of thefirst band may be defined as 996RU. When the first band is a 160/80+80MHz band, the tone plan of the first band may be defined as a tone planin which 996RU is repeated twice. When the first band is a 320/160+160MHz band, the tone plan of the first band may be defined as a tone planin which 996RU is repeated four times.

The EHT-SIG may include EHT-SIG-A and EHT-SIG-B (or EHT-SIG-C field).The EHT-SIG-B may include resource unit (RU) information. Thetransmitting STA may inform information on the tone plan of the firstband through the EHT-SIG-B. In addition, EHT-STF, EHT-LTF, and the datafield included in the second control field may be transmitted/receivedby multiple RUs included in tone plan of the first band.

FIG. 28 is a flowchart illustrating a procedure for a receiving STA toreceive a PPDU according to the present embodiment.

An example of FIG. 28 may be performed in a network environment in whicha next-generation wireless LAN system (e.g., IEEE 802.11be or EHTwireless LAN system) is supported. The next-generation wireless LANsystem is a wireless LAN system improved from the 802.11 ax system, andmay satisfy backward compatibility with the 802.11ax system.

The example of FIG. 28 is performed by a receiving STA, and thereceiving STA may correspond to an STA supporting an Extremely HighThroughput (EHT) WLAN system. The transmitting STA of FIG. 28 maycorrespond to an access point (AP).

This embodiment proposes a method and apparatus for transmitting andreceiving PPDU based on multiple RUs configured by a combination betweensmall-RUs. In this case, small-RU means a resource unit having less than242 tones. In particular, this embodiment proposes multiple RUs in which26RU and 52RU are aggregated in each 20 MHz subchannel of a band fortransmitting the PPDU.

In step S2810, the receiving station (STA) receives a Physical ProtocolData Unit (PPDU) through a first band from a transmitting STA.

In step S2820, the receiving STA decodes the PPDU.

The PPDU includes a control field and a data field.

When the first band is an 80 MHz band including first to fourth 20 MHzsubchannels, the first 20 MHz subchannel includes first multipleresource units (RUs) in which a first 26RU and a first 52RU areaggregated. The first 26RU is an RU located in the middle of the first20 MHz subchannel. The first 52RU is an RU having a lower frequency thanthe first 26RU and is adjacent to the first 26RU.

In this embodiment, the first band may be divided into four 20 MHzsubchannels. For example, the first to fourth 20 MHz subchannels may bearranged in order from a subchannel having a low frequency to asubchannel having a high frequency. For example, the first 20 MHzsubchannel is a 20 MHz subchannel having the lowest frequency (or aprimary 20 MHz channel), the second 20 MHz subchannel is a 20 MHzsubchannel having the second lowest frequency (or a secondary 20 MHzchannel), the third 20 MHz subchannel is a 20 MHz subchannel having thethird lowest frequency (or a lower 20 MHz channel among a secondary 40MHz channel), and the fourth 20 MHz subchannel is a 20 MHz subchannelhaving the highest frequency (or a higher 20 MHz channel among the 40MHz channel). In addition, puncturing in units of 20 MHz may beperformed in the first band.

The second 20 MHz subchannel may include second multiple RUs in which asecond 26RU and a second 52RU are aggregated. The second 26RU may be anRU located in the middle of the second 20 MHz subchannel. The second52RU may be an RU having a lower frequency than the second 26RU andadjacent to the second 26RU.

The third 20 MHz subchannel may include third multiple RUs in which athird 26RU and a third 52RU are aggregated. The third 26RU may be an RUlocated in the middle of the third 20 MHz subchannel. The third 52RU maybe an RU having a lower frequency than the third 26RU and adjacent tothe third 26RU.

The fourth 20 MHz subchannel may include fourth multiple RUs in which afourth 26RU and a fourth 52RU are aggregated. The fourth 26RU may be anRU located in the middle of the fourth 20 MHz subchannel. The fourth52RU may be an RU having a lower frequency than the fourth 26RU andadjacent to the fourth 26RU.

The control field may include allocation information on the first tofourth multiple RUs. The receiving STA may decode the control field andidentify the RU allocated to itself among the first to fourth multipleRUs. That is, when multiple RUs are allocated to the receiving STA basedon the control field, the receiving STA may receive a data field throughthe allocated multiple RUs. For example, when all of the first to fourthmulti-RUs are allocated to the receiving STA based on the control field,the data field may be received through the first to fourth multiple RUs.

In this case, the first to fourth 26RUs may be RUs consisting of 26tones, and the first to fourth 52RUs may be RUs consisting of 52 tones.

This embodiment proposes an aggregation method between RUs allocated ineach 20 MHz subchannel of an 80 MHz band. However, it is not limited tothe transmission of the 80 MHz band, and the present embodiment isequally applicable to the transmission of the 20 MHz band, the 40 MHzband, the 160/80+80 MHz band, and the 320/160+160 MHz band. The toneplan of the 20 MHz band and 40 MHz band defined in the EHT wireless LANsystem is the same as the tone plan defined in 802.11ax. Since the toneplan of the 160/80+80 MHz band and the 320/160+160 MHz band repeatedlyuses the 80 MHz band tone plan, the allocation of multiple RUs in the160/80+80 MHz band and the 320/160+160 MHz band may be extended andapplied for every 80 MHz channel. Specific examples are as follows.

When the first band is a 160/80+80 MHz band including first to second 80MHz subchannels, each of the first to second 80 MHz subchannels mayinclude fifth to eighth 20 MHz subchannels. The fifth, sixth, seventh oreighth 20 MHz subchannel may include fifth multiple RUs in which a fifth26RU and a fifth 52RU are aggregated. That is, the present embodimentmay be performed in units of each 80 MHz subchannel for the 160/80+80MHz band, and specifically, in each of the 80 MHz subchannels, multipleRUs in which 52RU and 26 RU are aggregated for each 20 MHz subchannelmay be allocated.

Similarly, the fifth 26RU may be a RU located in the middle of thefifth, sixth, seventh or eighth 20 MHz subchannel, the fifth 52RU may bean RU having a lower frequency than the fifth 26RU and adjacent to thefifth 26RU. In this case, the fifth 26RU may be an RU consisting of 26tones, and the fifth 52RU may be an RU consisting of 52 tones.

The control field may include allocation information on the fifthmultiple RUs. The receiving STA may decode the control field andidentify the RU allocated to itself (fifth multiple RUs). That is, whenmultiple RUs are allocated to the receiving STA based on the controlfield, the receiving STA may receive a data field through the allocatedmultiple RUs. For example, when the fifth multiple RUs are allocated tothe receiving STA based on the control field, the data field may bereceived through the fifth multiple RUs.

When the first band is a 320/160+160 MHz band including first to fourth80 MHz subchannels, each of the first to fourth 80 MHz subchannels mayinclude ninth to twelfth 20 MHz subchannels. The ninth, tenth, eleventhor twelfth 20 MHz subchannel may include sixth multiple RUs in which asixth 26RU and a sixth 52RU are aggregated. That is, the presentembodiment may be performed in units of each 80 MHz subchannel for the320/160+160 MHz band, and specifically, in each of the 80 MHzsubchannels, multiple RUs in which 52RU and 26 RU are aggregated foreach 20 MHz subchannel may be allocated.

Similarly, the sixth 26RU may be a RU located in the middle of theninth, tenth, eleventh or twelfth 20 MHz subchannel, the sixth 52RU maybe an RU having a lower frequency than the sixth 26RU and adjacent tothe sixth 26RU. In this case, the sixth 26RU is an RU consisting of 26tones. The sixth 52RU is an RU consisting of 52 tones.

The control field may include allocation information on the sixthmultiple RUs. The receiving STA may decode the control field andidentify the RU allocated to itself (sixth multiple RUs). That is, whenmultiple RUs are allocated to the receiving STA based on the controlfield, the receiving STA may receive a data field through the allocatedmultiple RUs. For example, when the sixth multiple RUs are allocated tothe receiving STA based on the control field, the data field may bereceived through the sixth multiple RUs.

The control field includes a first control field supporting a legacywireless LAN system and a second control field supporting an 802.11bewireless LAN system. The second control field may include auniversal-signal (U-SIG) or an extremely high throughput-signal(EHT-SIG). The second control field may include allocation informationon an RU to which the data field is to be transmitted. This embodimentdescribes a case where the RU to which the data field is transmitted isa multi-RU in which a plurality of RUs are aggregated with each other.The RU means a resource unit in which the data field is transmitted.

In addition, when the first band is an 80 MHz band, the tone plan of thefirst band may be defined as 996RU. When the first band is a 160/80+80MHz band, the tone plan of the first band may be defined as a tone planin which 996RU is repeated twice. When the first band is a 320/160+160MHz band, the tone plan of the first band may be defined as a tone planin which 996RU is repeated four times.

The EHT-SIG may include EHT-SIG-A and EHT-SIG-B (or EHT-SIG-C field).The EHT-SIG-B may include resource unit (RU) information. Thetransmitting STA may inform information on the tone plan of the firstband through the EHT-SIG-B. In addition, EHT-STF, EHT-LTF, and the datafield included in the second control field may be transmitted/receivedby multiple RUs included in tone plan of the first band.

5. Apparatus/Device Configuration

The technical features of the present specification described above maybe applied to various devices and methods. For example, theabove-described technical features of the present specification may beperformed/supported through the apparatus of FIGS. 1 and/or 19 . Forexample, the technical features of the present specification describedabove may be applied only to a part of FIGS. 1 and/or 19 . For example,the technical features of the present specification described above areimplemented based on the processing chip(s) 114 and 124 of FIG. 1 , orimplemented based on the processor(s) 111 and 121 and the memory(s) 112and 122 of FIG. 1 , or may be implemented based on the processor 610 andthe memory 620 of FIG. 19 . For example, the apparatus of the presentspecification may receive a Physical Protocol Data Unit (PPDU) through afirst band from a transmitting STA; and decodes the PPDU.

The technical features of the present specification may be implementedbased on a computer readable medium (CRM). For example, the CRM proposedby the present specification is at least one computer readable mediumincluding at least one computer readable medium including instructionsbased on being executed by at least one processor.

The CRM may store instructions perform operations comprising: receivinga Physical Protocol Data Unit (PPDU) through a first band from atransmitting STA; and decoding the PPDU. The instructions stored in theCRM of the present specification may be executed by at least oneprocessor. At least one processor related to CRM in the presentspecification may be the processor(s) 111 and 121 or the processingchip(s) 114 and 124 of FIG. 1 , or the processor 610 of FIG. 19 .Meanwhile, the CRM of the present specification may be the memory(s) 112and 122 of FIG. 1 , the memory 620 of FIG. 19 , or a separate externalmemory/storage medium/disk.

The foregoing technical features of this specification are applicable tovarious applications or business models. For example, the foregoingtechnical features may be applied for wireless communication of a devicesupporting artificial intelligence (AI).

Artificial intelligence refers to a field of study on artificialintelligence or methodologies for creating artificial intelligence, andmachine learning refers to a field of study on methodologies fordefining and solving various issues in the area of artificialintelligence. Machine learning is also defined as an algorithm forimproving the performance of an operation through steady experiences ofthe operation.

An artificial neural network (ANN) is a model used in machine learningand may refer to an overall problem-solving model that includesartificial neurons (nodes) forming a network by combining synapses. Theartificial neural network may be defined by a pattern of connectionbetween neurons of different layers, a learning process of updating amodel parameter, and an activation function generating an output value.

The artificial neural network may include an input layer, an outputlayer, and optionally one or more hidden layers. Each layer includes oneor more neurons, and the artificial neural network may include synapsesthat connect neurons. In the artificial neural network, each neuron mayoutput a function value of an activation function of input signals inputthrough a synapse, weights, and deviations.

A model parameter refers to a parameter determined through learning andincludes a weight of synapse connection and a deviation of a neuron. Ahyper-parameter refers to a parameter to be set before learning in amachine learning algorithm and includes a learning rate, the number ofiterations, a mini-batch size, and an initialization function.

Learning an artificial neural network may be intended to determine amodel parameter for minimizing a loss function. The loss function may beused as an index for determining an optimal model parameter in a processof learning the artificial neural network.

Machine learning may be classified into supervised learning,unsupervised learning, and reinforcement learning.

Supervised learning refers to a method of training an artificial neuralnetwork with a label given for training data, wherein the label mayindicate a correct answer (or result value) that the artificial neuralnetwork needs to infer when the training data is input to the artificialneural network. Unsupervised learning may refer to a method of trainingan artificial neural network without a label given for training data.Reinforcement learning may refer to a training method for training anagent defined in an environment to choose an action or a sequence ofactions to maximize a cumulative reward in each state.

Machine learning implemented with a deep neural network (DNN) includinga plurality of hidden layers among artificial neural networks isreferred to as deep learning, and deep learning is part of machinelearning. Hereinafter, machine learning is construed as including deeplearning.

The foregoing technical features may be applied to wirelesscommunication of a robot.

Robots may refer to machinery that automatically process or operate agiven task with own ability thereof. In particular, a robot having afunction of recognizing an environment and autonomously making ajudgment to perform an operation may be referred to as an intelligentrobot.

Robots may be classified into industrial, medical, household, militaryrobots and the like according uses or fields. A robot may include anactuator or a driver including a motor to perform various physicaloperations, such as moving a robot joint. In addition, a movable robotmay include a wheel, a brake, a propeller, and the like in a driver torun on the ground or fly in the air through the driver.

The foregoing technical features may be applied to a device supportingextended reality.

Extended reality collectively refers to virtual reality (VR), augmentedreality (AR), and mixed reality (MR). VR technology is a computergraphic technology of providing a real-world object and background onlyin a CG image, AR technology is a computer graphic technology ofproviding a virtual CG image on a real object image, and MR technologyis a computer graphic technology of providing virtual objects mixed andcombined with the real world.

MR technology is similar to AR technology in that a real object and avirtual object are displayed together. However, a virtual object is usedas a supplement to a real object in AR technology, whereas a virtualobject and a real object are used as equal statuses in MR technology.

XR technology may be applied to a head-mount display (HMD), a head-updisplay (HUD), a mobile phone, a tablet PC, a laptop computer, a desktopcomputer, a TV, digital signage, and the like. A device to which XRtechnology is applied may be referred to as an XR device.

The claims recited in the present specification may be combined in avariety of ways. For example, the technical features of the methodclaims of the present specification may be combined to be implemented asa device, and the technical features of the device claims of the presentspecification may be combined to be implemented by a method. Inaddition, the technical characteristics of the method claim of thepresent specification and the technical characteristics of the deviceclaim may be combined to be implemented as a device, and the technicalcharacteristics of the method claim of the present specification and thetechnical characteristics of the device claim may be combined to beimplemented by a method.

What is claimed:
 1. A method in a wireless Local Area Network (LAN)system, the method comprising: receiving, by a receiving station (STA),a Physical Protocol Data Unit (PPDU) from a transmitting STA; anddecoding, by the receiving STA, the PPDU, wherein the PPDU includes acontrol field and a data field, wherein based on a bandwidth of the PPDUbeing an 80 MHz and including at least one 52+26 tone multiple resourceunit (MRU), the 52+26 tone MRU is obtained by a combination of a 52 toneRU and an adjacent 26 tone RU within the same 20 MHz channel, whereinthe 52 tone RU is an RU located in a lower frequency than the adjacent26 tone RU, and wherein the adjacent 26 tone RU is an RU located in themiddle of the same 20 MHz channel.
 2. The method of claim 1, wherein thedata field is received through the 52+26 tone MRU, wherein the adjacent26 tone RU is an RU consisting of 26 tones, wherein the 52 tone RU is anRU consisting of 52 tones.
 3. The method of claim 2, wherein the controlfield includes allocation information on the 52+26 tone MRU.
 4. Themethod of claim 1, wherein based on the bandwidth of the PPDU being160/80+80 MHz and including the at least one 52+26 tone MRU, the 52+26tone MRU is obtained by a combination of a 52 tone RU and an adjacent 26tone RU within the same 20 MHz channel in each 80 MHz frequency block.5. The method of claim 1, wherein based on the bandwidth of the PPDUbeing 320/160+160 MHz and including the at least one 52+26 tone MRU, the52+26 tone MRU is obtained by a combination of a 52 tone RU and anadjacent 26 tone RU within the same 20 MHz channel in each 80 MHzfrequency block.
 6. A receiving station (STA) in a wireless Local AreaNetwork (LAN), the receiving STA comprising: a memory; a transceiver;and a processor operatively coupled to the memory and the transceiver,wherein the processor is configured to: receive a Physical Protocol DataUnit (PPDU) from a transmitting STA; and decode the PPDU, wherein thePPDU includes a control field and a data field, wherein based on abandwidth of the PPDU being an 80 MHz and including at least one 52+26tone multiple resource unit (MRU), the 52+26 tone MRU is obtained by acombination of a 52 tone RU and an adjacent 26 tone RU within the same20 MHz channel, wherein the 52 tone RU is an RU located in a lowerfrequency than the adjacent 26 tone RU, and wherein the adjacent 26 toneRU is an RU located in the middle of the same 20 MHz channel.
 7. Amethod in a wireless Local Area Network (LAN), the method comprising:generating, by a transmitting station (STA), a Physical Protocol DataUnit (PPDU); and transmitting, by the transmitting STA, the PPDU to areceiving STA, wherein the PPDU includes a control field and a datafield, wherein based on a bandwidth of the PPDU being an 80 MHz andincluding at least one 52+26 tone multiple resource unit (MRU), the52+26 tone MRU is obtained by a combination of a 52 tone RU and anadjacent 26 tone RU within the same 20 MHz channel, wherein the 52 toneRU is an RU located in a lower frequency than the adjacent 26 tone RU,and wherein the adjacent 26 tone RU is an RU located in the middle ofthe same 20 MHz channel.
 8. The method of claim 7, wherein the datafield is transmitted through the 52+26 tone MRU, wherein the adjacent 26tone RU is an RU consisting of 26 tones, wherein the 52 tone RU is an RUconsisting of 52 tones.
 9. The method of claim 8, wherein the controlfield includes allocation information on the 52+26 tone MRU.
 10. Themethod of claim 7, wherein based on the bandwidth of the PPDU being160/80+80 MHz and including the at least one 52+26 tone MRU, the 52+26tone MRU is obtained by a combination of a 52 tone RU and an adjacent 26tone RU within the same 20 MHz channel in each 80 MHz frequency block.11. The method of claim 7, wherein based on the bandwidth of the PPDUbeing 320/160+160 MHz and including the at least one 52+26 tone MRU, the52+26 tone MRU is obtained by a combination of a 52 tone RU and anadjacent 26 tone RU within the same 20 MHz channel in each 80 MHzfrequency block.